Paul Fjeld's page in particular is a good source of information on the changing colour scheme of the LM. [link to home.earthlink.net]

The unusual faceted design of the LM ascent stage skin and the small triangular windows came about as a result of the the refinements the Grumman thermal engineers made as the design evolved, starting from the design on the left, with its large windows and rounded structure, evolving towards the final version right.

[link to www.armaghplanet.com]

Fjeld tell us that the Grumman engineers changed the paint scheme on individual panels to tune the temperature of the skin to the desired level.

K