Ahhh, that's a very very good question.
You do have to disclose that the selvage has been hinged, because that affects the plate number single premium significantly (don't ask why).
However, you can quote the MNH price for the single as reference, since technically the actual stamp is not hinged. Again, you DO have to disclose the selvage is hinged so that there is no misunderstanding.
As a selvage collector, this has always been one of my pet peeves. People please quit using the selvage to hinge stamps! Put the damn hinge on the stamp and leave the selvage MNH! Many a good selvage inscription has had its gum ruined by this nasty practice!
