Well I've waited to put in my $.02. I think it's up to the owner. It's not like he's some newbie who doesn't know what he has. I think if I were you I'd just take it as a great compliment and give it my BEST shot. Take your time, it's been waitin' over 60 years already.
I agree with Sticks & Strings...
"Is there any way you can leave the writing on it or maybe slice the piece off with a band saw and put in the sight window area like an inlay or something to preserve it in some way."
I think that would be cool, and a way to save some history. I also agree to document all work on it. Give it a go, and do us all proud, we believe in ya.