That was Burt Kellerstedt's gun and was a total restoration. Many of the parts were the wrong ones for that serial because nobody knew much about Gas Traps back then. The last part he needed for it was a numbered stacking swivel... I had recently found one and assumed they must be common, so gave it to him. It took me 20 years to find another one.
The gun sure wasn't that nice when I examined it in the Seventies.