Sounds like a single stage setup. My other machine is a single stage also, but it looks more like an auger than a drum.
BTW, pics of yours (when it thaws out) or it didn't happen.
To encourage classic snowblower conversation I'll point out something ironic. REO was bought by Wheel Horse Products. They were known for yard tractors, but obviously were interested in expanding. This machine is from a transition period before it all got labeled Wheel Horse.
View attachment 111142
At this point they were manufacturing Tecumseh engines under license. If they installed an engine manufactured by Tecumseh the engine would be painted black instead of red.
The ironic part is that Wheel Horse eventually became TORO, which is what I bought to replace the REO.
Or at least supplement it.