I'm looking at a rifle that has Weaver rings from the 30s-early Forties. The rings require the disassembly of a K 2.5-K3 or the like to mount the scope. How can I minimize scoping fogging in a non gas filled scope?

Fogging is condensation.
I'd dry it in a dry box, coat the exterior lenses with an anti-fogging wipe, and keep the rifle/scope combo at ambient for the season.
I do that for muzzleloaders, predator rigs, and I get good results as far as condensation, until it gets close to zero. Then one errant breath, and it'start over.

Store it outside on the day of the hunt, there will be minimal temperature change...Steve