Sounds like you have most of the bases covered. So yeah, probably check the gage first. Not sure what brand you are using but I have some Autometer digital that seem spot on. Always nice to have three methods to check ... then you can get a consensus.
Initially higher temps coming off highway to street is normal in most cases.
Was the factory stat for that model 195? In that case I'd expect temps from 190 - 200 normal. Often installing a lower range stat doesn't lower temps because the cooling system just isn't designed to shed enough btu's to run that cool, so the stat will just run wide open all the time when up to temperature and the cooling system will seek its own balance between heat the engine produces and heat the system can shed.
On the highway, when steady cruising for a while and it hits 210 with the AC on ... will it sit there for an extended time without rising? If so then I'd expect the cooling system is at least working as it should, it's not being overloaded to the point it goes into a thermal runaway and keeps going up.
Kind of sounds like it's operating normally except the gage is showing higher than expect temps.
I live way up north ... so we lean a bit more to the 50/50 coolant mix for the freeze protection
And as DanC says ... my 2011 GMC truck also has been running right on 210 for years now with never a problem, I very rarely even hear the electric fans come on (it doesn't have a mechanical fan) If those temps are suitable for a vintage engine I don't know.