Unfortunately I only added the serial pins to one unit and I have no idea which one it was now. It's gonna be a crap shoot finding it lol. While adding the serial pins was very easy, disassembling these units was challenging. I will have to re-read the instructions again. lol
There may be some useful information in this thread as well.
I will try to find the unit with serial pins installed early to mid next week and do some testing.