Joined: Feb 2012
Posts: 19,352
Likes: 5,470
From: Rochester, NY
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
I suspect that this lug set was made with a 3 speed in mind. Or at least with a roller guided rear gear cable routing at the seat lug. Hence the stud on the Rh side of the seat lug. The shell looks to have the "foundation" for an oil port (or, if a modern part, a Zerk nipple). This is another common detail BITD. Andy.