Welcome! Yes, those front PTOs can be a pain to get off, just use a lot of PB blaster and let it soak for a couple days. The 6 set screws will eventually come free. Also, I use heat... I have a blow torch and blast the begeezes out of the PTO to get the set screws off. I would think most of the PTO is fine, just don't force it off. It probably will need some new springs which you can get at any hardware store as well as a polishing.
Nice find on the 149!