As a former surfer and scuba diver I have been following this thread with interest. The housing David mentioned is the Rolleimarine. In the '60's you could buy a plexiglas housing for most any camera. It would seem to me that just about any M/F housing would be from 20 to 40 years old. That would mean replacing all of the O-rings at the very least. That means the exact O-rings. And be sure to lube with petroleum jelly.
A holga is one thing, taking a prime Rollei TLR or a 'Blad and sticking it into a 30 year old housing of unknown history is bad idea.
You can buy a new Nikonons V and O-ring kits from B&H. This is where 35mm shines.