The crude construction smacks of a commercial kit similar to a pair of brass 8 wheel tenders I own. One of them came to me mated to a heavy Mikado kit from the late 40's. IIRC, the kit was manufactured by Hines, according to DeBruin. It too is relatively crude but proportioned correctly for a USRA copy. It lends itself well to additional detailing, which I performed on mine. Details specific to the AT&SF Berkshire prototype could be easily added and rearranged when building since the boiler is not cast.
pics are available if desired once I'm back at my computer.
Bruce