That SOUNDS about right...They (Honda) did a similar stamping thing when replacing early CX500 alternators to show it had been done....
My ONLY objection is: IF he does not have a title, he doesn't legally "own" the bike, so he cannot transfer "ownership" by selling it even with a signed and NOTORIZED "Bill of Sale"......
This is NOT to say it's a stolen bike, (and it's probably not, many "older" bikes have been sold/traded/bartered/abandoned or whatever without the titles getting legally transferred each time, and the paperwork is now hopelessly lost and untraceable and/or unobtainable...)
Just that I won't be the person buying it..... Without appropriate paperwork, I won't even take a "free" bike..... Steve