These bagpipes (right) showed up in Connecticut. I encountered them at the Schenectady Highland Games. Of course, they look like Henderson bagpipes, and they are, inside and out, however they were stamped "Williamson" between the cord holders.

"Williamson & Jeffray" are listed in Jeannie Campbell's book as making bagpipes between 1948 and 1950. Both were employed by Henderson bagpipes prior to this time.  Williamson was an apprentice at Henderson's just prior to Jack Dunbar and was known to be an excellent turner. Jeffray tied-in pipe bags and otherwise made the finished product ready for the customer. 
This Williamson bagpipe was offered up on EBAY. The chair is incredible!
Williamson