Aging Report & Mac's

What’s the best way to track aging Macs? It doesn’t look like the agent pulls the BIOS release date.

BIOS date is a horrible way to report on device aging anyway, the report is pretty much useless because of that. For Windows, short of looking up the warranty and manufacture date the best you can get is the the System Volume Information folder’s creation date. Maybe you can find some similar folder on a Mac that persists refreshing/upgrading the OS. Then have it pushed to a custom field and use Asset Audit Report to display them.

With HP computers you can get the age of a PC by its serial number.
Solved: Use serial number to age computer - HP Support Community - 7287820

and you can get the serial number on the commandline with
Get-WmiObject Win32_BIOS | Select-Object SerialNumber

Perhaps Macs also embed the age in their serial numbers, and perhaps you can get the serial number of the Mac on the commandline.