Bob,
Your serial number reveals that your gun is stainless and was machined for Detonics by Cal Foster, who later formed Caspian Arms. Therefore it's not a MKII; which were nickle plated. If it has a matte finish and a fixed sight, and possibly says Combat Master on the sides of the slide, it's a MKV. If it has shiny sides and an adjustable sight, it would be a MKVI. If it has no sights, it's a MKVII.
Good luck on your goal. ...Deeton