Hello. I have a 1990s era specialized hard rock sport, and I noticed significant play in the BB. Upon removal and further inspection, both the cups and the axle are pitted. Although the pitting is minor and would probably not present an issue for a while, I would prefer to just replace the BB.

The BB seems to be of the 3N size as demonstrated on Sheldon Brown's Bottom Bracket Size Database. And it is being used with SAKAE SR Cranks.

The suggested symmetrical equivalent is 124mm. Unfortunately, I am having trouble finding modern BBs in this size. I see the BB UN-300, but it is a 122.5 mm. What are my options that arent extremely expensive? Any way to correct the chainline of the 122 mm option?

Thank you in advance!