Obtaining the MAC address after theft

Perhaps there may be some misunderstanding between the MAC address and that of Find My Mac status.

(These have different meaning, as all online devices have some kind of address, even some printers, etc ~ and the identity of a lost/stolen product you seek to locate does not use a "MAC" address to help find said product.)

MAC address - Wikipedia

A media access control address (MAC address) of a device is a unique identifier assigned to a

network interface controller (NIC) for communications @ data link layer of a network segment.

https://en.wikipedia.org/wiki/MAC_address

If you have set up your Apple product to use the find mode for your lost or stolen device ahead of that happening, there may be a chance to determine its location. IF you have not set it up ahead of that occurrence, that generally wouldn't be helpful to law enforcement or recovery.

• iCloud : Lock and track your device using Lost Mode in Find My iPhone:

https://support.apple.com/kb/ph2700?locale=en_US

• Set up Find My iPhone on all your devices - Apple Support:

https://support.apple.com/en-us/HT205362

• Get help with Find My iPhone - Apple Support:

https://support.apple.com/en-us/HT204233

and another item that may or not be of help

Get Help using the Find My iPhone app - Apple Support

https://support.apple.com/en-us/HT203384

Sorry to not be of more direct help in this matter.

It is usually on the shipping label/box. But that is the only place I can think of. Why do police want that?

What do you think the police are going to be able to do with the MAC address?