Brimfield Flea Market Finds - Model Railroader Magazine

 Just got back from the Brimfield (MA) flea market with a couple of cool items.  Bought 7 Midgetoy metal pieces for $27 total, Marx tinplate NYC pacemaker caboose for $5, a stamped metal Katy sign for $7, an earlier Atlas GP38 (Conrail 7658), and a Hobbyline NKP Berkshire kit (with all the parts, partially assembled). 

Just curious on two things: the GP38 has the old Atlas "split" fuel tank, with a seam of sorts down the side.  Is this prototypical (I haven't seen one), and is there a replacement tank to fit in place?

Also, anyone build one of the Hobbyline Berkshire kits?  I'd like to finish it as a B&A model, and potentially power it.  Anybody try this?  Thanks.