[Mos6502]

I guess since I'm already several posts past it,  I'd answer James' question here.

The Red Injun flywheel is cast as a solid piece with the "spokes" in relief on one side.  The other side is flat.    
Originally this engine was apparently made by Wyandotte in the city of Wyandotte... they went under at the end of the 40s/early 50s - and then the "Major Toy" Red Injun appeared at that time.
Considering that Wyandotte's steam engine was called the Red Injun too, and essentially similar in design, I assume that the Major Toy simply took over manufacture of the engine (Major Toy was also located in Ecorse michigan, which is right next door to Wyandotte)

I wouldn't go so far as to call the Red Injuns rare - but they are unusual to find (they are considerably harder to find than Weedens, Empires, and even Fultons - but usually several show up on ebay per year).  There's several variants.  The earliest versions (by Wyandotte) have a cylindrical firebox (which is cast metal), much like that of Weedens - and a flywheel with open spokes.   Later the firebox was changed to the haystack shape.  Then Wyandotte went under.   Major Toy revised the engine with a solid flywheel.  
There's also an electrically heated version, and one with a whistle.  The cylinder design also was altered slightly at some point, and so was the routing of the steam pipe. Eventually Major Toy moved production to Detroit.
I don't know when they stopped making them - I assume probably before 1960, but I really don't have the faintest idea.  While there's plenty of info on Wyandotte - details about Major Toy are near impossible to find.

I should also note that the retail price for these engines was $3.95 when new.