Of course without seeing the guts of the inside, you may never know what makes it tick but...Gizmo built a small trailer smoker with a back end firebox last year that easily has the similar lines that you show here...look up his build known internationally as "Egor"
Make no mistake, there ain't no powder in this Puff ! And... I'm not really a crazy person but I play one in real life
I agree w/ DC. Or it cudve been a roto. But appears a lil tight at the top for a roto if it had the shelves and not a single spig. But if it was a roto you shud be able to see the shaft/housing from the outside.