Just got it back from HAAS music
http://www.haasmusic.com/, they machined a replacement 4th valve bearing cap out of one from a french horn for $50. I did the Rick Denny Du-Bro linkage conversion also
http://www.rickdenney.com/valve_linkages.htm
I stripped off the multiple layers of lacquer, shined it up and applied a coat of car wax. Looks, works and sounds pretty good.
Still unknown manufacturer, but is stamped Western Germany
I'm excited for community band rehearsals to start again.