"Ray" wrote
The house was built in in BC Canada in 1975


The picture you see is shooting thru a small access hole, To get in
there with soldering torch , cutting tools, etc is going to take major
work. I read that these things can be rebuilt without removing the body.


That may make it easier, but after 35 years, chances are the housing and
insides are crap and the unit will have to be replaced anyway.

Many regulators have a metal tag under the adjusting screw. That will
have the pressure and the model number. Were any other houses build on the
street at the same time? Maybe you can see theirs better. You can try
matching it up with major brands, such as Watts.