I have restrained myself from posting on this thread because I am partially guilty...but I have a lot of mixed emotions about this. I fitted a swiv-o-matic cymbal mount and bass drum spurs on a 28" blue and olive badged Ludwig bass drum. It was a concert drum, it had no mounts or spurs. At least now its usable for me and its WAY cool! In many cases as new and more robust hardware came out back in the day...people modded their drums too. Off the top of my head, Ginger Bakers silver sparkle set had swiv-o-matic hardware and I know there are more. George Way drums were often also sold with swiv-o-matic hardware from the factory as was Camco (arguably not a "mod" then, but I digress). You could easily say that in the early 60's, Rogers hardware was the modern day Pearl hardware...it was everywhere.
I restored some Sonor teardrops for a friend. The first thing he wanted was Pearl bass drum spurs. When I restored it, it got all original hardware and a bass drum hoop claw. He said it won't work, he needs the Pearl legs because the bass drum moves. I showed him how to set it up using the claw and factory spurs and guess what...it don't move. My argument is, was, and always will be if John Bonham didn't complain about his bass drum walking around using vintage hardware....nobody else should. If he could figure it out, so can you (minus the old nailing the hoop to the stage trick...LOL!!!). I think sometimes people missed out on learning how to use vintage gear, or simply look to continue emulating who they did when they were young.
On the other side of that coin, I believe it should be stated nobody is talking about drilling in a one of one left drum. These are typically common run of the mill production shells that can still be found everywhere today. If a piece is legitimately rare (not uncommon, not valuable, not I wish it was rare....I mean honestly rare)....then yeah don't drill it. Find someone to trade or sell your rare piece and buy something that fits your needs. If anyone really wants to get upset about modifying or even trashing gear that is now appreciated, look at Tweed era Fender amps. Through the 70s and into the 80s people painted them black to look like modern amps, ripped out the old Jensen speakers, cut the cabinets up, tore the tweed off, and ultimately just trashed them. Into the 90s you couldn't give a Tweed away. I have seen pictures of music stores with 40-50 Tweed Fenders piled up outside because people didn't care about them (same with Tweed era Gibsons too....BTW). Now...a Tweed Bassman is considered the holy grail of amplifiers and fetches north of $6,000. Its a small example of how one generations trash or tools of the trade becomes another generations treasure.