Have two Atlas SD 35's, one, the R2LC 07 board, that failed. I replaced it, with an R2LC08 board, available at that time. There were some differences, associated with detail lighting, requiring small wiring changes. IMO Mike CT.
Edit/add: These models also came with a blind driver axle set, that could be swapped-out, with the installed center flanged driver axle, on the SD trucks, for operation, on smaller diameter curves.