Even if rivet lines are plainly visible, there's still the question of spacing as far as the rows of rivets and the space between the individual rivets, and how that may, or may not, match up with the putative patch. That's going to have to be a very fine tolerance indeed for the putative patch to be generally accepted as what we're all hoping it is.
LTM,
Monty Fowler, TIGHAR No. 2189 EC