I haven't seen your WIPs, I'll go check them out.

The modeling chapter in 4.5 Fundamentals would definitely work for 6, but other chapters might be outdated. If the same author has an updated book with pretty much the same chapters, I'd go for it. In a pinch, though, you're not really going to miss out on anything as a beginner. Modeling is modeling in Maya, and you have to get over the first few humps before what version you're using really matters.

Good luck!