After some deliberation, I decided to get the dirt model back on the road (so to speak). Some of this comes from the fact that the dirt model still has the MFG plate on the main fork tube (the 'S' model does not) and some from the fact that I can fix the dirt one quicker...and cheaper.
Well, it is pretty definate that the 'S' model motor is in the dirt model frame.
During tear down I found metal shavings in the frame oil tank. And when I drained oil I found the shavings...but only in the frame oil tank. The engine has no shavings in it and seems pretty clean. No rust or wear on anything...
Also figured out that the 'dangling' wire on the shifter side of the engine is something used on the 'S' model. Probably neutral detection.
Pulled apart both carbs to find varnish and badly fitting float needles. I guess that would be part of how the gas would keep flowing every now and then.
Oh, I may not have mentioned that during my test ride phase I shutdown the bike and gas kept flowing. The PO 'fixed' this by whacking the side of the carb with a piece of PVC pipe until it quit. Carb body is scarred from this.
If it seems like I was not impressed with this person's mechanical skills...you would be correct. The only stupid questions are those not asked, and it looked like this guy never asked anyone for help.