I got my starter back yesterday. Hand picked up and hand delivered by the local, Cleveland rebuilder (Custom Electric Service, they are about 60 miles away). All work done for a mere $65
I am impressed with their willingness to work with me on Concours details (regarding painting) but we lost out on discussing the cardboard or paper gasket detail because of the primary issue inside about the field winding insulation. They ended up using another core 'body' instead of the one I sent because of the difficulty in removing the windings for replacing them. They did return my original nose cone, strap and abendix cover. Per our discussion, he was able to find in his core pile a Concours correct case "without stampings" as required for an early 67 year model so I am please with the results. They sent it back with a light coat of grey primer, avoiding spraying onto the nose cone housing and cable stud. (I'll paint it myself with my next batch of semi-gloss black parts)
Now, back to the band or strap gasket material issue. I'll give them a phone call and see if they have a product they use. They DID install a gasket under the abendix cover and my understanding is that is "concours correct" but maybe we should discuss this too?