Interesting. From the first pictures I saw with it all complete my first thought was "rebuild the carbs, 3000 mile tune up, then quick flip." Does the engine turn over? If it does it's a shame it got taken apart. So where it stands now it is quite firmly in the category of "basket case." This means it is not worth much. Most of the value in these bikes is not in stuff like the engine. Most of the value is in the cosmetic stuff--tank, seat, chromed parts, exhaust, side covers, engine covers that usually get road rashed, nice gauges, etc. etc. From the condition I saw I don't see you really making a whole lot parting this thing out. What is the bike worth to you? Not much. The $120 figure might seem low but the bike was devalued once it was taken apart. It's now a basket case, and basket cases aren't worth as much as a whole, complete bike that could be road worthy from a day's work.
If I take my bike to a painter and say I want the frame and tank etc. painted he might charge me $500 for the paint job, but he will tack on another $1000+ just for all the labor and specialty knowledge of taking everything apart and putting it together the right way.
Was it running before the teardown?