Hi Bob,
I think $50 for that set is a steal! Heck the box is probably worth that if it's in decent condition.
I have the same model but it's, oh what's that word, the one pros use to evaluate the condition of vintage items... oh yes, hammered!
It is a 630 based chassis, my set has a 10FP4 CRT, the aluminized version of the 10BP4, no doubt an aftermarket addition.