Well, in these years of production the "Waffenfabrik Mauser" roll mark was on the left receiver rail. Most of the time the receiver ring was marked with WFM and year of production again, but this is not consistent. The Mauser "ton" logo was only introduced in the 1920s. "Actions only" for sale to others were only marked with the Commercial serial number on the underside. Other markings were unnecessary, as Mauser was the only source for M98 actions. So if you see a Mauser actioned rifle by S&S,Merkel or others, you may only recognize an original Oberndorf commercial action by the "earmarks", that is bolt-handle shape, long firing pin nut, shape and size of trigger guard, absence of seperate DST housing. Any visible inscriptions and numbers will be those of the company who put the rifle together or even the retailer. If you ever encounter one of the early "Original Brenneke Leipzig" rifles, close inspection will reveal a commercial action by Mauser and, in hidden places, the ESHA stamp of Schmidt & Habermann, Suhl, who put together nearly all repeaters for Brenneke.