The offer seems a bit high on the price side to me. You have no Guarantee on the condition of the two HT power supplies or the HeNe tube. The stepper motors , seem the most interesting to me, but again without proper schematics and proper mounts it would be difficult to use. The polygonal scanner is just a liquid sky scanner that you could make yourself quite easily.
However if you are interested in optics and experimenting and feel like biting the bullet, you could do a whole lot worse , I guess.