in the mid / late-80's, the world was hi-ten, the world sport was cro-mo main tubes. Full cro-mo frame started with the traveller. The serial number of the OP's bike starts with "G", indicating it was built by Giant. The lack of indexing makes me believe this bike was from '87 or so. I believe by '89, it came outiftted with indexing shifting. It was an OK bike, but if I had one, I wouldn't bother purchasing new wheels for it, I'd use it as is. I believe that the OP's bike has 5 speed threaded freewheel, meaning an upgrade to a 7 speed freehub will need to include cold setting the frame to accomodate the wider hub. And to the OP, sorry for not explaining, F.Q/R stands for Front Quick Release, pertaining to the front hub.

Also to the OP, one other thing I wanted to throw out was to take a look at the rear chainstays for a white sticker aprox 1/2" square that says "Giant" followed by a four digit number. If it's present, that's the date code that should also be stamped into the head badge (the numbers that should be in the head badge are very tiny).

Still a nice bike for $25.

GregG