I've actually been using several RT7D20s for years now. Also use a similarly aged IBM keyboard, but don't have that one at hand.
I got these as these were dirty cheap (like €2 each) and I should have 1 or 2 extra spares (my mother also 'stole' one due to her keyboards having the tendency to either die or to malfunction). These were basically NIP (New In Plastic-wrapped-stuff) 🤣
I fear that my gray one is dying though (some keys don't want to always cooperate and it's seen years of heavy use, even ate together with me many a meals 🤣), kinda gotten attached to it. My black one is still in good working order. These seem to be virtually indestructible.