I could provide an assessment based on the Canadianicon market, however the US market would surely be different, personally I have not seen a discernible difference in prices based on manufacture in my own region.

As an aside what you have there is a Webley Mark VI (6) that was license built at RSAF Enfield between 1923-1926 if I remember my dates right. As you may have guessed it would have originally been chambered in .455. As a caution, avoid firing modern production .45 ACP ammunition through this revolver, some have done so, but is a stress on the design, most shooting enthusiasts use a custom handload that runs at reduced pressure with moon clips.