In the area where I live, there is a good market for 2-cycle Lawn Boys because some property owners have steep ditches to cut. 4-stroke mowers suffer from oil starvation when operated at these angles. But, as far as what one will pay for a used older Lawn Boy is hard to determine. A few years ago a fellow that owned a small engine shop told me he could sell them all day for $125 because of the demand for ditch cutters. There are also a few guys around here that like to collect the older ones but beauty is in the eyes of the beholder. Another rule of thumb is that one man's junk is another man's treasure. It is anyone's guess what your mower is worth.
Speaking for myself, I picked up three non-running 2-cycle Lawn Boys this year. On each one I removed the engine and replaced crankshaft seals, exhaust port seals and other various small parts. One deck and shroud got repainted, one needed a new coil, and all of them got a good cleaning. One of them was a 1984 Commercial that I got for free. One was a 1980 F engine model with factory yellow colors that I paid $50 for. Another was a 1978 D engine model with self propel that I paid $75 for.
Some guys will say that I paid too much for the ones that cost me something, but to me they were both priced at a level I was willing to pay for the condition they were in.