I have built up two different older Raleighs, into very nice 'beater' fixies. A Sportif, which was from like 79-81 (as near as I could determine), and a Team USA replica from 83. Both were solid Reynolds frames and the Sportif was actually nicer for a conversion, being without downtube shifter braze-ons and a rear deraileur hanger.

I am no bike snob and $50 is great for any steel lightweight bike as far as I am concerned.