Beseler is now a shell of itself, but they are still open for business, so a telephone call might work.

FWIW, on their website they have exploded parts diagrams for both the current 67xlc and Printmaker 35/67 enlargers, and the 4" condenser assemblies for those two enlargers have the same part number: 10-42098.

Here is the website link: http://www.beselerphoto.com/parts/