Yes, this is a G4. Well, actually, a GV4 as Tango described it, who I just bought it from on the Buy/Sell forum (which he said he bought it used from someone on here too). Looking at pics of the actual G4, my pack looks like the precursor to the G4; the only noticeable different is the strip of webbing in the center of the pack (side opposite to shoulder straps) starting just above the mesh and used to close the top.

Anyway, I was loading it with my summer bag inside the rolled pad with nothing underneath. If I were to load it with my large (volume) winter bag, I'm thinking it'll work really well to put that on the bottom, then use the rolled pad frame on top of my bag. I guess I could try it too with my summer bag and use clothes to beef up the volume I'm putting down there, to then put the rolled pad on top of. Only thing then, there isn't a whole lot else to pack inside the rolled pad frame if I'm stuffing the bottom of my pack with bag/clothes. So perhaps that is my answer, stuff the bottom with bag/clothes, and use the pad as a folded back sheet (as is suggested) rather than a rolled pad frame.