Thank you for the welcome and advice!
I measured the stem to be 22.2mm just above the HS, not sure if that's the same as steer tube measurement; being a bike novice, I may be misusing some of the terms I picked up browsing this great forum.

I guess I should take the HS apart and measure, and also look for additional lettering.
I read about swapping the caged bearings for loose bearings but I'm leaning toward r/r the entire HS so I won't have to touch that part again for some time.

Is there much difference between the Tange Levin and Falcon HS(~$40 +s/h)? I am hoping to replace parts as close to original if possible.

I would like to overhaul everything but it's going to take years with all my other projects needing attention around the house (per my beautiful wife) so what I will do is post current pics because I don't know when I'll be able to post finished pics.