If you read OOT's description on the product page, Dolly is simply a morph of G2Female.  No new rigging.  No new UV's.  It's not a base, it's a morph set.  It doesn't even have a new obj file.  If it had a new geometry file, I'd consider it a base.  Otherwise, it's really just another morph set. 

They said it's a character and if it's different from the normal proportions of the Genesis2Female it's most likely has adjusted rigging in order for it to work in Poser as scaling alone will not work. Genesis also doesn't use obj files at all, and uses a concept of gene pools. It's a change in thinking, but it is generally separate characters as each character is added to the gene pool and you need the base character to use characters based on it. The fact that all the figures are compressed into one mesh solves the problem of vendor support for new characters. Think about it: How many characters have come and gone because there wasn't any clothing or textures for it?