Thank you Jim for your insight and information!
I am planning to keep the speed knobs because I prefer the look and usability, but if I can find original knobs at a reasonable price they might add to resale value if I decide to sell later on..or they might not. I've seen sets of four 60's witch hats with gold inserts sold for 200-250 USD but since I live in Europe they would cost nearly 350 with shipping and customs.
Anyway, I'm skipping the ones I linked, nice repro knobs can be found for much less money..But if anyone knows a reputable dealer for vintage Gibson parts in Europe, please let me know!
-Tero