[SFfiredog]

The key words here are "good shape"
95% of the 40 year old original OEM dampeners I looked at have all those nice cracks and chunks missing from the vulcanized rubber ring between the hub and shell.
If you find and OEM NOS, hermetically sealed, climate controled environment stored balancer, I would have no problem using it.
I have seen the result of a dampener failing. It ain't pretty.
If you do use an old dampener, make sure you check top dead center on the engine and verify the timing marks on the dampener.
I have seen them all over the place.
Then make sure to mark the hub and shell to verify if the shell moves because the rubber is no good and you can't set your timing anymore. and also you might as well add the rest of the timing degree numbers and then mark the shell ever 90 degrees to help valve adjustment. or...
Hang the old unit on the wall and buy a new dampener.
Do you remeber the scene in "Casino" when all the old Mafia bosses were in the back room of the courthouse trying to decide if they should whack a potential "loose end"
Everyone vouched for him untill the last boss said,
"Why take a chance? Anyway, that's how I see it"

I agree.

--Mike