The decks seems like a medium sized issue - common problem in 70s boats so not sure it's a deal killer.
The iron fuel tanks is different - getting the iron tanks out of a Rafiki is almost impossible, they have to be cut up and things taken out to make room to get to them. So they are a major issue IF they go bad and rust on you. Depends on the grade of material, but it is a known issue that has to be addressed by some owners.
Still a great boat!