If a stamp has some damage, minor or otherwise, it must be genuine. Correct?

That statement is wrong. Just because a stamp is damaged doesn’t mean that it hasn’t been altered in some way. It could still be reperforated. It could still be regummed. And so forth. Here is why.

Case one. The stamp may have become damaged after the stamp was altered. At the time of alteration, the stamp was sound. Through improper handling, the stamp may have developed a crease, a thin, or some damaged perforations. It happens.

Case two. It is true that a sound copy is worth more than one that has faults, even tiny faults. Let’s take, say, Scott #245, the $5 Columbian from 1893. Suppose you have a mint copy with no gum and some damaged perforations. Suppose a never hinged copy has a catalog value of $10,000.

A copy without gum and some damaged perforations is worth a couple hundred dollars. If you add gum to it and leave the perforations alone, you don’t have a $10,000 copy. But maybe you have, say, a $2000 copy with the damage. You now have a copy that is worth five to ten times what it was worth without gum. If you find an unsuspecting buyer, you hit the jackpot and made a bunch of money.

Altered stamps are not always the pristine copies with never hinged gum and perfect centering. Yes, those stamps bring more money. If you’re not too greedy though, you can alter a stamp of lesser quality and still make a large profit.

As a buyer of stamps, every stamp, no matter how perfect or imperfect, should be examined. Does it look regummed? Was the stamp reperforated on one or more sides? Anything is possible.

The main point is that the price of the stamp is the determining factor. For example, suppose you have a no gum copy with damaged perforations of stamp that catalogs $10. Will you take the time to regum it to make a worthless, damaged copy into, say, a $4 copy, assuming the damage can’t be easily covered up? Probably not. While inexpensive stamps are just as susceptible to altering as rare stamps, most people aren’t going to alter an inexpensive stamp to eke out a few dollars profit. The monetary reward isn’t there.

When dealing with stamps that catalog $50 or more and the possible monetary gains increase, then yes, someone may take the time to alter the stamp to make a profit. The higher in value the stamp, the more chances there are for someone to alter it.

For example, if a stamp with $50 catalog value has minor damage that is easily removed, sure, someone may take the time to alter it. If that same stamp has damage that isn’t easily covered up, no, I doubt someone will take hours to alter the stamp. It’s a lot of time for very little money. There are other stamps out there with higher catalog values that yield much more money when altered.

If you buy damaged copies of expensive stamps because you can’t afford the sound copies, there is nothing wrong with that. Even if the stamp was altered, it’s not going to change the value of the stamp much at all. For example, suppose you are buying a Scott #245 without gum and a large thin that is very poorly centered for $50. That’s a fraction of the price of a well centered, sound copy. Even if the stamp was reperforated on one side, the stamp is already so cheap that the reperforation isn’t a major factor in determining its value. If the reperforation was noticed, maybe the stamp would now be $40 instead of $50.

When buying inexpensive copies of valuable stamps, yes, it is possible that the stamp may have been altered at some point. Dealers aren’t going to go to great lengths to detect alterations on such copies. The stamp is already very cheap. Dealers spent lots of time scrutinizing the $5000 copy. That same level of scrutiny won’t be applied to the faulty $50 copy.

Lastly, let’s talk about hinging. A hinged stamp could still be regummed.

Case one. Someone many years ago may have legitimately hinged the regummed stamp to put it in their album. It happens.

Case two. Would someone regum that Scott #245 and add a hinge mark to cover their tracks? Maybe. The person altering the stamp knows that a very valuable never hinged copy is going to be scrutinized by the buyer much more closely than a hinged copy. Still, the reward is there. Hinge it and make it a $2000 stamp instead of a $10,000 stamp and hope the buyer takes the bait.

As a buyer, hinged stamps should still be scrutinized for original gum. A hinge mark does not imply that it is original gum.

I hope this has given you some insight into why even faulty or hinged stamps may have still been altered. It pays to inspect every stamp.