Well, nobody responded, but I did find answers to the questions, so I'll post them for posterity. The cap is actually an original Buescher cork grease container - it's just coincidence that it perfectly fits the neck tenon. No telling how it would up in the horn. Thanks Matt at Music Medic for the information. I repadded the 1925 horn with Roo pads, retaining the original snaps, but cementing the pads for stability. The horn plays beautifully. The ergonomics are not that of Selmer sba, but it's actually easier in some ways than my 41 Conn 6m, especially the low left pinky keys. It sounds very good, a bit brighter than the Conn, a few minor intonation issues, some of which I can address with setup. There is no altissimo F key, but I guess that's what sopranos are for. Ron