We are looking for part numbers of PCB boards of SBEC2 so far I have found
463-2377 I have only found these with T1 and TIII configurations.

451-7652 I have multiple V6 versions such as 3.0 and 3.3 of this , I also have one as turbo T1 that was purchased over the parts counter.

I suspect that the 463-2377 is an early issue SBEC2 but I am looking for your thoughts.