Good luck with your double bell.
Tidbit of good news. The first valve is probably common with a King Single Bells of the era.
Is valve 1 missing in its entirety or just the stem and button? Stem would probably be fairly easy.
See if your local repair person can sort out the 4th valve without damaging anything.
4th valve would be the toughest to find a replacement for.
Some quality silver polish and you have a nice wall hanger right now.
Check the serial number to verify the date, start e-mailing some of the savvy repair folks about the 1st valve, and you may have a player in a reasonable time.
Best of Luck with it,
Jim
Jim Babbitt
1960s 4 valve and 1971 3 valve Besson New Standards (Denis Wick 6BM) for regular playing
1936 Conn 5 valve 30I Double Bell (Bach 6-1/2AL) General Purpose Back -Up
1924 Buescher 5 valve (the Denis Wick is close) and 1940 Holton 5 valve (Bach 6-1/2AL) Double Bells for kicks.
1860s OTS Saxhorn when history is required (the Denis Wick fits)