This plane is in virtually NEW condition, finish is all original. The round bottom looks like it's factory done but I have no way to prove it. A knowledgeable collector tells me the #3415 is a regular production transitional plane. The VBM markings he says are 1902 vintage. If the round bottom is not factory done it's certainly the work of a first class craftsman! T are no left over tool marks, no scribe marks, nothing to indicate how it was done. Thickness is consistent from one corner to the others, curvature is so perfect I would say it was likely done with a machine tool or at least a specially set up wood working machine. The only thing that looks less than perfect is the way the corners of the cap iron were radiused a bit to match the cutter better (see close-up). T is no rust on iron parts! I blew the dust off but this plane has never been cleaned because it's never been dirty! As much a mystery as the curved bottom is why it was never used. I see a trace of blue paint on the bottom just forward of throat w someone made a couple strokes on something but t is really no wear showing on the bottom. No chips or cracks in handle or knob, original varnish and japanning are 99 percent at least.