I know the original owner and he gave me the bike so I am confident that he is the original owner and knows the history of the bike and has no reason to tell me anything else. He originally wanted me to modernize the bike but did not like the options for getting modern derailleurs on it.
I believe it does have the original Delrin front derailleur (the one that slides sideways?). It is not cracked although the plastic does look dried out. I don't think I would go the triplizer route due to cost and as my vintage bikes (down to about 8, all road bikes, all XL, my size) are more of a hobby and I ride mountain, gravel, touing more and I have modern bikes for that. I am going to try to find a wider range cassette though.
The vintage bikes are just cool, fun to work on. and fun to ride on occasion.