Very nice score. That's easily worth about 4X what you paid. If its' the right size, I'd call it a keeper. I have an 87 Record made from the same 502 tubing. It's a nice rider, not high end, but still a nice ride. I think you'll find those rims are buldge bead and will be able to hold 100PSI tires. I stay away from Kevlar bead tires because those old 27" rims were not made for those type tires. A better choice would be the wire bead tires that are readily available at Performance or Nashbar. I have the same derailer on the Record, taken off a Marathon I used to own. It's a good performer. I think you're going to like the Marathon, good luck with it.