I welcome this discussion here, as it certainly pre-dates 1933 and starts/falls in the Republican era. It is also great to see your Beagle breeze by... getting old, we have an elderly wanderer ourselves, though she sleeps more than wanders...
Standard Modell variations, since John Wall passed there is something of a void in trying to interpret the numerous variations, one of my earliest projects were trending Standard Modell's and Mauser Banners (K), generally I break them down by dates:
Mauser Banner K's (98k design), basically the DRP's and DR's which are dated 1933-1934
B-prefix Standard Modells, they start seemingly early, a very few are in the B100xx ranges, the earliest rifles are dated 1934, so it is reasonable safe to assume these came after the orders for the DRP & DR. They become more common around B38xxx range and are undated by then. They become common by B39xxx-B400xx ranges. They range up to B823xx ranges. The earliest of the B-prefixes are Chinese contracts and the Ethiopian contracts fall right after (B216xx-B292xx), almost all 1934 dated receivers. Rarely encountered are rifles before the B35xxx range, when seen they are typically Chinese, Ethiopian, or some escapee the SS picked up. There are a few A-prefix rifles but so rare as to defy categorization.
The SS/SA (Gr.B.B. - Ch.d.A) variations follow, mostly 1934 dated, but a few 1933. They are rarely seen and usually make people stupid.
There is a separate, or seemingly so, series that have more distinctive Chinese markings, follow a more normal serialing pattern (4-digits over a suffix) the Nationalist Chinese FP. I do not follow them as close, but they seem fairly common.
I separate the not attributed Mauser Banner K's into different groups, the ranges intermingle with the SS/SA variations, many probably went to the supermen, but maybe police. Most are 1934 dated (some earlies are 1933, up to 619xx). There are queer birds here too, T-prefix rifles, C-prefix (not DR's) a few others, generally they range to 948xx
The 1941 Mauser Banners are last, quite a few of them. Basically SM built up as 98k within the 1941/byf serial range.
Generally the earliest SM are so rare they are impossible to study, or trend, I assume most were consumed in China, I doubt many went to Germany. Jon Speed stated that parts for the SM were made in Germany and shipped to Switzerland (1931) for export to other countries, this was to get around the restriction placed upon Germany not to import or export military equipment of any kind (1920's international agreement based upon the Versailles Treaty, but it wasn't German law until 1930 - it was one of the last "big deals" the English, French and Belgians extracted from the Germans, - they pushed hard to curb the proliferation of police too, but the Germans wouldn't budge on the police, but after intense negotiations and compromises, the Germans passed "German laws" to make it illegal to import or export military equipment, they also gave in on some fortification compromises, - let some Belgian Officers watch them blow up emplacements as i recall... ), this probably accounts for the illicit workaround sending parts to Switzerland to transship to China etc.. but it is less clear how many rifles were assembled in Germany for German customers or who the customers were.. small numbers either way until 1933. I would think the survival numbers would be high for any sold in Germany, they certainly are common for the ranges we know they were sold in Germany...