If your Erfurt Luger is any date other than 1914, it was not an Artillery model. Beginning in late 1916, all Erfurt Lugers were to have the notch for the Artillery rear sight cut into the receiver. Most were, but not all. The ONLY year Erfurt made the Artillery model was 1914. All other-year Artillery models will be DWM.
Is the "MA536" on the pistol or the mags? I can't tell from your post.
Is the "MA536" on the pistol or the mags? I can't tell from your post.