I bought a used Beseler enlarger. The lens board that came with it had a 50mm El Nikkor lens. An omega enlarger also came with the deal and it had an 80mm El Nikkor. I swapped the 50mm for the 80mm since I want to print 6x7 negatives. I was reading that there are different lens boards for different focal length lens ranges. 8021 would work for the 50mm and 8023 for the 80mm. I'm assuming I have the 8021 but there are no markings on it, just a pilot light.

How can I tell for sure which model board I have? Will the 80mm lens work OK with what I've got?
Thanks,