itb - Maker's names are like trademarks. A. Lancaster may not have been actively trading - as in a shop by that name when your gun was sold. However, you can bet someone held the name. "Lancaster" was famous and would have been more help to a gun than the name of some lessor known maker/shop owner/retailer. This was fairly common practice - consider that Thorne became Lancaster. There is no fakin' of the gun or the name, just an application that may slightly misguide modern buyers. Most Birmingham BL's bear the name of someone other than the actual maker. Keep in mind that Brit guns were made in a trade environment.
