Peter, most definitely. I, too, know a lot of people that do just that. I'd equate that to someone installing a 1N007 diode in place of a cooked selenium rectifier. You'd never know it was there unless you removed the chassis, and it does the intended job of rectification. Though, there always seems to be a catch. You have to check and adjust your B+ when replacing a selenium rectifier with a diode. It's not hard, just time consuming at times. And yes, I suppose I could install a more modern solution in Oz's radio, but between what I found here at home and the spare Mexico Oz found for next to nothing online Oz would likely end up spending much more money. Not necessarily for parts, but the time involved in creating that make shift solution would likely prove to be cost prohibitive. Not to mention the amount of room inside of Oz's radio is next to nothing.
Regarding the obsessive aspect of restoration....I'm one of those crazy people that will gut an old original paper/wax capacitor and put a newer, smaller one inside, fill it with wax, and then reinstall it. However, I'll only do that with really special Tv's or radios that are unusual or extremely original and nice cosmetically.
MBZE.....That quotation isn't true at all. That has to be one of the more far out, bombastic, and humorous comments I believe I've ever read. That makes about as much sense as an 8 amp fuse working in the U.S. but not in Europe because they're on different lines of latitude and longitude. haha If that were the case, then Oz's radio I'm working on wouldn't work because his is a European model. Think about it this way.... consider the two radio stations 105.4 and 106.1. In order to get to 106.1 you have to pass 105.4. If there is anything being received at that 105.4 frequency the radio is going to pick it up. The radio doesn't know the difference. It merely does its job of receiving, amplification, demodulating, multiplexing (for stereo), oscillating, and sending an output to the speaker(s). The radio does't care on the 88.1 to 108 scale where the signal is coming in. The part about Europe using even numbers on the right side of the decimal used to be true, but I don't know if they still do that or not. I would imagine they do since we still use odd numbers.
Though, do bear in mind that the early European radios would often have an FM scale that would only go up to the 102-103 frequency range. Have a look at Oz's radio in the first picture on this post. You'll notice that the FM band only goes up to 103. Naturally, we wouldn't be able to pick up any radio stations above 103, but I can promise you these radios will work here or anywhere else in the world as long as a signal is being transmitted.
I only mentioned about Scott's comment being an interesting thought because we don't have Longwave here, and Shortwave is rarely used here. My thought process was that if someone had a 3 or 4 band radio with pre-sets here in the U.S. then converting the LW and SW to additional FM or AM buttons would be useful. Though, there are some radios that couldn't as easily be done to, such as a Monte Carlo TR (LW/SW/BC only) a Le Mans TR (SW/BC only), or a California (BC only). But it's not common to come across those anyway.
I'm a member of Radio Museum, and I've thoroughly enjoyed the website over the years. The vetting process used to be pretty invasive, but I don't think it's too bad anymore. Though, you still have to contribute as often as you can. They're on a point type ratio system. If your ratio of downloading schematics to contributing schematics/sales figures falls more in favor of downloading schematics then they'll ban you until you repair the ratio. It's definitely a haven for fellas like me. Though, I wish I had known about it before I bought so many Riders and Sam's volumes. They are absolutely massive books. The Riders books are around 2 feet by 1 foot, and 4-6 inches thick! I don't mind though. About 99% of the time I prefer an actual book anyway.