Posted by Peter Hirsbrunner on January 07, 2004 at 11:44:37:
In Reply to: Serial numbers on Yorkbrunner posted by Chris on January 06, 2004 at 14:30:18:
Hirsbrunner instruments with rotary valves have the serial number on the bell near the connecting top bow.
Hirsbrunner instruments with piston valves have the serial number on the valvecasing, either on first, second or fourth.
Hope this answers the question.
Peter Hirsbrunner