1968 CB350 Carburetor Issues x 2

My 1968 CB350 has engine number CB350E-1042106.  My issues:

1) My right hand carb has a leaking Overflow Drain Nipple protruding from the bottom of the Float Bowl.  It appears to only leak when I switch to the Reserve tank.  Any ideas what could be causing this leak?  What do I need to replace to eliminate this leak?

2) My left hand carb does not have an Overflow Drain Nipple.  Could I have two different versions of the carbs that were built for the CB350?  Or, is this the correct configuration?

Thanks so much for any advice or guidance.