just rubbing down the SM frame and thought that i should measure the rear dropouts.
it's only 120mm.
my rear hub is 126mm - so i think i will have to play around with spacers as i don't want to force this one like my NR.
question is will a 6 speed freewheel fit, or shall i make do with 5?

Spreading a steel frame to 126mm is trivial. Have a shop do it so they can check the alignment afterward.

thought about getting it re-spaced, but i would rather spend some money on a goodpaint job...it's 90% done....and as it's 35 years old i didn't want to stress more than it was designed for - does that sound silly?
and my hands stink from rubbing it down earlier too!

Don't even bother getting it respaced. Just pull the stays apart a bit as you install the wheel.

Suntour Ultra-6 spaced freewheel will fit right in without any spreading at all.

I don't recommend this approach. 6mm is a large spread. It will change the angle of the dropouts relative to the locknuts by about 0.5 degrees. Even though this sounds small, clamping the wheel into non-parallel dropouts induces stress in the rear axle, making the axle more susceptible to bending.

Either get the reat triangle cold set or use a narrow, six speed freewheel, as previously suggested.