I remember that arrow symbol you are talking about and I believe, but not certain, that its Shimano Light Action. I think some people refer to this group as the early 105 though.

Is this bike grey with yellow lettering?

It depends on what you want to do with the bike. Are you looking to get it road worthy at the bare minimum cost.
Friction shifters are fine, but SIS shifters are just much nicer to use. You should be able to pick up a set of Shimano 600 SIS 6-speed shifters for next to nothing. Then of course you could use the $2 wheel you got and go with 8-speed, if you were looking to replace the freewheel and shifters anyway.... The 130mm spacing on the 8-speed hub will work fine with the 126mm spacing on your steel frame. Shimano even put rounded nuts on the axles then to help the stays spread.

A fluted seatpost (like the SR Laprade) is what your looking for to keep the vintage look if your going for that. Its probably a 26.8 diameter or maybe even 25.4. Sorry, I'm using my Laprade on my single speed. I think the saddle was a suede Selle San Marco Concor, or at least they looked just like the current Concor.