Well I used to fix no2 binoculars which are from around that time and used well into the 1990's. The screws on the originals are BA or British association a wierd British screw pitch that are used on small arms and optics.
If it becomes foggy because of a bad seal (every sight will eventually loose it seal. It's a rapid temperature change that causes the condensation) there should be a screw on the side of sight usually painted red. That can be removed and a dedicating unit attached to it to dessicate the air inside.
The weird British BA screws are hard to find but I’ve found a source for them in the UK. I guess they are used in the model train collector hobby. You probably know that but I’ll post the link for others that might need some. The Parker Hale side mounts in their #1 and #4 Enfield custom sporters use these BA screws when they’ve been factory drilled and tapped.
https://www.modelfixings.co.uk/ba_cap_screws.htm




















































