Sellers: Do you mark boards?

[modessitt]

One trick is to write your initials on the bottom of all socketed chips.

Another is to desolder a flyback (or other large part), write your initials on the board underneath, then put the part back in. Even where they to find it, they're not going to be able to fake your handwriting...

 

[EVB]

I concur. A hi-res pic may not prevent anything but at least you will be 100% positive you have been jacked.

There is no need to mark a board. Simply take a high res picture of the board so that you can read the details on EVERY chip. Make sure this picture is included with the sale / auction post.

There is 0 chance of you receiving a different board back that will have the exact same date codes on every single chip on a board, let alone same manufacturers for that matter for any 74LS* chips and most others.