Significance of suffix

[Doubs]

I would add barrel length and model to that serial number/date and also maker.

As an example, lets use 1916 as our date. There is a standard 4" barrel 1916 DWM serial number 1234b, an Artillery model 1916 DWM serial number 1234b AND an Erfurt standard 4" barrel 1916 serial number 1234b. If the pistol has unit markings, I'd record those as well.