"Bill" wrote

But, what you can do is to have a cavity into which you pour a filler with
a unique composition for each item. or if you want to use RFID, have a
cavity filled with a unique epoxy with a chip in there. You may also
look at how companies like CISCO do this

I had thought of a drilled tapped cavity, with a screw in brass plug. Epoxy
would work. Do you think that a reader would be able to pick it up? One
could drill the hole close to an edge so that the metal thickness would not
be a lot.

With a drilled, tapped hole, the chip COULD be removed, but it may have to
be removed for identification anyway.

With an epoxy application, it would HAVE to be read in the cavity. Do you
know if the reader has to be on any particular axis to read it? If not, it
could be read through the epoxy at the end of the hole.

Either way, the thing could be defeated, but in those cases, ownership would
revert back to the manufacturer, and authentication of company policy could
be presented to any LEO in case of dispute.

Steve