Hi David,
I can only give you the procedure for getting serial numbers when you have the "whole Mac" running and go from there.
1. Click on the Apple Menu and from that pull-down menu select "About this Mac." A window will pop, showing basic info like processor type and OS X version.
2. ON that window - select "More Info."
This launches System Profiler and the first category in its (Left hand column) is "Hardware." In the description box (right hand side) you will see the complete details for the Mac - including serial number (2nd to last item in that list).
To my knowledge, if you were to put that cloned drive in an enclosure then boot it from whichever Mac you now have: the System Profiler would naturally profile the Mac you're using, not the Mac you've sold.
So that answer is: unless you can get the person who bought the Mac to follow the above instructions and report the serial number to you, you might be out of luck.
Another possibility is that you might be able to get such a serial number from Apple if you have the original purchase document. (I haven't paid attention to my old receipts from Apple - so I don't know if the serial number appeared on them. But there's a good chance they do show that info.)
If you bought that old Mac, new, you may have other options
for getting the product's serial number from an old email or
other receipt from sales, service, AppleCare or other source.
Products bought online from Apple's store generate an email
receipt and also paperwork from the transaction should have
the serial number.
A clone of the software on an external hard disk drive should
not have recorded the information from the original computer
since that would've been supported by the Mac's Firmware.
That data is not normally in the hard disk drive; though it is
available to System Profiler, probably on demand when run.
Someone technical may be able to substantiate the path
the computer takes to display the information stored in
firmware when the software displays this during inquiry;
and IF any hidden data may have survived the cloning,
where it may be found. I doubt a clone would have the data.
If that were available in the clone, so would the firmware version.
As that is generally in the same location the serial number would
be saved. A clone can boot an identical hardware version of a
computer it was made from, and it "knows" to show the current
serial number and technical data from the new host, in Profiler.
So, that data is probably as distant from the Clone as the Mac.
You may be able to contact the new owner and ask, for your
records (having transferred ownership & responsibility) to get
the serial number and reaffirm the date of transfer, too. - You
should have made out a bill of sale including the SN just in case
the computer became a hotbed of illegal yet traceable activity!
Lucky you, if that were so, it'd likely be traced via internet, first.
{Just kind of kidding, there.}
Or check with the place you bought the computer from to see
if they may have a record of the transaction or have better ideas.
Apple sales support & AppleCare would be likely, if new to you.
My newer computers had email receipts and paperwork in boxes.
If you still have the original box it was purchased in it will be on the box. There's no need to go into the "More Info" part of Apple's System Profiler as you can simply click on the gray coloured listing of the OS version. It will cycle through other useful bits of information including the serial number.
You can also get the Serial Number by booting into single user mode (command+s) on startup and issuing:
system_profiler SPHardwareDataType
It should list the Serial Number that way. If the logic board has been replaced you may not get the serial number. Unless the repair specialist used the Firmware Restoration/Serializer Utility CD to rewrite the original serial number back to the replacement board.
+{And if he sold the box with the computer, he would have one more+
+place to ask the new owner to look for the serial and model numbers+
+should the current owner not want to boot the computer for the info}+
As macnoel started out, click on the Apple at the upper left of the menu bar and choose "About this Mac".
That's all the further you need to go to find the serial number. Where it says "Mac OS" in big letters, the OS version number is just below that. If you click on that spot, it rotates between three pieces of information, the OS version, the OS build number and your Mac's serial number.
+{ if he calls or emails the new owner, they can do that;+
+he's sold the computer and it is not physically present }+
Thought I'd re-state the concept; since the clone does
not have that information in it, so looking into a backup
from another computer, won't supply info from the host
computer no longer available on-site.
If there is a way to do what the OP asks, please state it.
I'm curious, since my clone from any computer won't
show me any firmware-based info from a Mac not there.
