Only to buyers looking for a reason to make a lower offer--as they're easily reproduced.

Exactly; and a little funny if you think about why it matters in one hobby...and wonder why it would matter in the other.

Let's see, with one with hobby, in order to fake serial numbers you have to locate the metal dies with the correct typeface, then remove the old serial numbers by adding new metal, spend a ton of time grinding & sanding to remove any evidence of tampering when paint is applied, and lastly strike the new serial numbers perfectly one-by-one into the metal with the dies.

In the other hobby, someone with computer graphics skills makes a white sticker in one-color ink that's a dead ringer.

Which is why I personally also don't assign any more importance to this than a nice warm fuzzy.

But hey, to each his own.