To clarify for others not in the original conversation....
The Don Hume fit code lists from the earliest any of us have to the latest do not list a number 6.
1-4 for S&W revolvers
5 for S&W Autos
7-9 for Colt revolvers - with 7 later including S&W L frame
10 for Colt GM autos
(Many more added in recent years.)
So what happened to six???
My inference was that there once was a 6 in the 1950's Hume galaxy, but whatever handgun 6 designated was no longer commonly holstered in the 1960's, so the number was dropped.
In the number sequence, 6 fit with Colt. Hmmm. A Colt no longer made after ...say 1941...but still in police service into the 50's.
I was disappointed that the L frame turned out to fit. Maybe it shrank....
OP's holster might have been mislabeled, but why would Hume have a stray 6 stamp lying around?
That the current Hume customer service would know that the holster was a special order, but not know for what detail is only slightly surprising given my experience with ammunition companies. (Per Red: The Bill Jordan picture indicates post-1982 production.)
If anyone has a Hume marked 6 for the fit code -- or better still, a catalog showing the mystery 6, we're eager to see it.