It sounds like it may be a fit for you. There are a gajillion websites on bike fit, google and read. I would ask some questions about the bike. Paint looks like 1985>
Miyata Bicycle Catalogs: Miyata Catalog 1985 It came with 27" wheels. Did the seller put some 700c's on there? That would be a good thing but ask why. Did the original wheels get folded in a crash? If these are 700c do the brake calipers reach properly? It also came with non-aero brake levers. This one has been changed to aero levers which are white and match the crank color. It has a white headset also. Perhaps someone did upgrades?
I hear you are in a hot market. The 310 is a decent rider. Triple butted main tubes. I like Miyatas. Go try it. If it all works and it fits make an offer. I could not sell a 25" 310 where I live for $275. Maybe that is fair market value where you live.
And the ad says 21 speed bicycle. Hard to tell but the crank does not look like a triple which it would be if it's 3x7. Ask about that. Sellers often get that math wrong.