A warranty block with no numbers is the next best thing to a matching numbers block.
A date correct block is next.
I've heard of people suspecting re-stamps being able to find the original numbers using all sorts of different methods like magnafluxing, thermal imaging, etc.
If you have a blank warranty block.....just leave it blank.
That way it can be used in any car made in that date range.
if you stamp it, you basically take that away, and sully the block more or less permanently.
