Transferring Files

If the old Mac has 10.6.8 or later use Migration Assistant

Move your content to a new Mac - Apple Support

If not, as the article says, you will have to manually copy files

Also not that if the old computer has 10,6.8 or earlier many apps will not run on Lion or later

Upgrading to 10.7 and above, don't forget Rosetta!

Also, if old computer has higher than 10.6.8, update for apps will likely be required.

Also, for some old attached devices like printers the manufacturer has not created drives for the later OSX versions.

Is that the kind of thing you can have done at the Genius Bar? I was kind of under the impression that sort of detailed transfer of personal files was up to the customer.