Changes in Upper Lucas Valley Eichler Design

Question: I have heard that the design and materials of the homes Eichler built in Upper Lucas Valley changed as he went along. For example, I have heard that in the later years one room was dropped from the design on the A-frame type model. Perhaps it was something off the kitchen? Also, I was wondering if the construction techniques and materials changed as time went along - for example, did things get better or worse? Lastly, do the newer parts of the Upper Lucas Valley development have better insulation than the older areas? Thanks!
-Tim