During the lead up to war, Danzig was the strongest maker of the 98a, in 1913 3658/a is the highest recorded, though a 8831/a is known but the serial is overstruck, uncertain if it was the original numeric serial but the "/a" is factory.
Only 7 Erfurt/13 are recorded, one of course is Jeff Noll's Erfurt/13 2133/a OMD.39
Here are the known rifles:
1913 Erfurt 5649 B.1.U.R.1306 (HH- German auction)
1913 Erfurt 6723 (B)
1913 Erfurt 8822 HZa rework (JimP)
1913 Erfurt 9923 (Vulch's in AUS)
1913 Erfurt 2133 a O.M.D. 39 JN
1913 Erfurt 2456 a 1920
1913 Erfurt 2475 a O.M.D. 49
1913 Erfurt 3658 a (looks original-matcher, top BP n/a)
1913 Erfurt 8831 a extensive rework, possibly Polish/NS rework, serial numeric overstruck to match components, probably lower serial in a-block