All the Webley built guns retailed by others will have a 5 digit number different than the serial # of the gun on the short rib if it's an early gun or on the forend loop. If it's on the loop you have to look close to see it.

The actions will also match up to what's listed in the Webley catalogs. My Evans are all built on Webley A&W.C action and my Manton retailed Webley is on the PHV1 action. There is a Webley catalog listed in the Double Rifle Photo section of this forum courtesy of Cpt Curl who has a Gibbs 450 built on the Webley A&W.C action that I wish he would be kind enough to send my way.