Brakes stickin after brake job
Those are Strange Engineering aftermarket axles; available for the Mopar 8-3/4' and have been drilled for 2 stud patterns or stud spline sizes.
http://www.strangeengineering.net/make-and-model/mopar/axle-packages-components/axle-only.html.
That sure is a Mopar PN on the center section. So I suspect the seller did not know what he was talking about.
Check your bolt pattern per the info above and be sure of the bolt pattern size. Then chekck the fit of the old drums.
I would ditch these guys; they are going to make it right so they avoid any reputation problems .... which they fully deserve. They probaly CAN do tires OK. But the idea of using the washers ON A SHOP SERVICED CAR is absolutely idiotic and beyond belief or acceptability, and shows amazing ignorance and no professional orientation whatsoever.
And please don't be humiliated; it's is just learning and just money, not your self-worth here. We've ALL been down this road a time or 2. This is one of the best, most helpful groups on the www, so you're in a good place.