not sure. The 1906 "model" is not near as common, as compared to the 1908 model. So although I am sure there are many 1906 types brought back, the 1908 model would be what, maybe 1.5 or 1.8 million to maybe a hundred thousand or less 1906 models from WW1 and WW2 eras? And that guess is counting ALL types of 1906's made. Many for US sales and other country's, but not German military (there were 1904 navy which have a grip safety and a few others, but the vast majority were 1908 models).
Plus, many commericial type wasn't what was issued to Germans (1906 type were for Brazilian and the Netherlands, and others I am sure.