CDM2 Servo Board. How to identify the version when the stickers are gone.

[rockrink]

I have on the bench a Conrad Johnson SD-1. It is based on the Magnavox FD2041. All the literature I can find says it uses a standard CDM2 transport. This one has no stickers on it and I am trying to determine which Pre-amp Servo board is in use. Virtually every SM I have read shows a 1K laser output adjustment pot at 3106. This board has a 4.7K pot. I have seen that pot used in CDM4 but not CDM2 before. I am trying to determine which version of the board this is. I attach a picture and wonder if anyone has any insight.