We have 5/16 x 2" top nail red oak over T&G subfloor. The house is near Philly and was built in 1950. Floors had carpet most of the time and are in good condition-- no pet stains, no deep scratches, etc. And, after all, they're floors and we don't need them to look perfect.

What were they typically finished with back in the day? Was thinking they could be buffed with a fine grit sandpaper, cleaned, and resealed with something like waterlox?

Main goal is to keep them protected going forward and slightly darken the honey-oak color.

We have about 1200 sqft and would prefer something more cost effective than a full refinish. Also, should a proper refinish cost as much as tearing out and replacing with 3/4 T&G? Seems odd to me but I know material prices have come down and skilled labor gone up.

Thanks.

Older floors were finished with varnish and can be coated again provided that there was never wax applied to the floor. Try a couple areas, after cleaning with paint thinner and steel wool, or turpentine.
When the floor is wet with solvent, this will be the color after a coat of finish.