RK8E controller board revisions - Chaos ahead, help needed

Hi folks, I'm currently dealing with some RK8E Omnibus RK05 controller board sets. I was unable to assemble even one stable RK8E from the stuff. I assume a high failure rate. But I also assume that I have board revision problems. I've been told that several revisions existed. And that there were compatibility issues and some kind of paper (which I do not have) telling what fits what. I don't even know if the revisions are PCB revisions like "M7104 B2" written in the etch or if there are also FCOs or alike that make boards with same etch incompatible to other boards. My personal RK8E passes all tests. It consists of: M7104 B2 M7105 B1 M7106 C But I have other boards flying around here as well. Do stamps like "310 D" on the backside of the boards have any meaning with respect to board revision or FCO level? Another question is how to get different board revisions associated with the right schematics. I strongly appreciate any piece of enlightenment since I'm currently getting depressed by that stuff. Even if I have bad boards - it won't make sense to try to repair something if the whole is inconsistent in itself. Many thanks, Philipp