Baldwin VO1000 prototype variations

I am thinking of buying a Weaver VO1000 and noticed in the Weaver catalog that there are several versions of the exhaust stack arrangement. It looks like there are three versions with one stack just in front of the cab, long medium and short. There is another version (Rock Island) with three stacks in about the center of the hood and another version with four stacks in about the center of the hood. I assume Weaver is following the prototype for the individual railroad. Does anyone know the story behind these variations? I also notice that this diesel does not have handrails on the outside of the side walkways, only on the inside similar to those on a steam engine. I never saw a diesel with handrails like this. Is this unique to the VO1000 or did other early diesel share this type of handrail installation.

See the bottom of the page for VO1000 pictures.

http://www.weavermodels.com/s06pg32&33.htm

http://home.bendbroadband.com/jacoxfamily/vo1000/vo-1000.html

Thanks chuckn, a wealth of information there. Didn’t take the time to read it al now but bookmarked it for future reading.