Henry III - the plugs are from Belgian beer bottles carefully sculpted to fit. If you want some I can send you a pair!
The eyelets are hidden in the window of the rear dropout and on the fork they are just above the dropout. Hard to see since they are very small. The fork was drilled for the eyelet. I had this done by Terry Shaw of Shaw's Lightweight Cycles in Santa Clara (no longer in business after a 35+ year run). I have most of a NR gruppo but that would involve raiding parts from my wife's road bike. My personal collection is C-Record and some Nuovo right now. At one point in time I took ALL of the NR stuff off of my wife's bike because she kept crashing. Once she was comfy with the bike I put it back on. :-)