Looking at the photos, I'd have to guess the frame at 48cm. Look for a two digit code on the underside of the bottom bracket near where the chainstays exit. Many early Specialized's had a size code stamped back there; this is not a part of the serial number, but rather a stand alone two digit number. As to value - I'd have to peg it at $4-500, but again, finding the right buyer is everything... Good luck!