It should be noted that Jerry has more often than not been one of the "shop boys".
Some interesting BS sessions have taken place over the years as to what a restored #20 should look like. My opinion and that of a few folks with each of us adding our personal nuance is that is should be blue printed as a Sumpter Valley engine. This includes being a wood burner, single air pump as delivered, what appear in photo to be Ohio injectors with the engineers in front of the cab, large headlight (anyone got a Locolight dynamo kicking around), boiler tube pilot as built, no power reverse and my personal preference is for the Radley and Hunter stack it sported for the first few years. Some of my friends will want a Rushton I suppose.
The photo of 20 after the roundhouse fire shows the stack I am partial to. The photo of 19 after rebuilding would be prototypical of 20 other than the stack.