Ive never actually built the device, so someone will have to correct me if im wrong here (but i do understand the schematics so its not exactly guess work on my part).
First off the boards are RC1a.
second, Ive never heard of a 4 board version. While there are a total of 4 boards to pick from you select 2 of the 4 to use. There is a main board, a Li-ion battery board w/antenna, a AAA battery board w/antenna, a no-battery board with just antenna. You basically choose 1 of the 3 power board depending on if you want li-ion, AAA, or no battery. I choose to include the li-ion because it is the longest lasting battery and it is rechargeable. Not to mention it is the most popular.
Your open-source friend,
Jeffrey Phillips FreemanCheck out http://www.syncleus.com for open source hardware, software, wiki, and shop. All kits and devices provide complete schematics and board layouts! Wave Bubble coming soon!