Might as well pick it up for that price and try it out if it is in very good shape. But then I always say you can never have too many coal stoves!!
Yes i am an addict and i only admit to having two working mag stokers, a semi working parts mag stoker and a mark 3 hand fed and I still look for a good deal to pick up another of either kind. Your affliction may not be as bad as mine!
Worst case scenario is that it performs the same as the Mark I and you will probably be able to sell it for same price as you bought it in order to upgrade to a larger 50-93 or Mark III or something similar in the DS line. You only lose time and energy moving it.