The first Chinese copies of the Browning M1900 were made at Nanking Arsenal. Production was reportedly ordered in 1913, but the rate must have been quite slow or the SNs started over each year because pistols 346 and 751 are both dated 1919. Pistol SN 900 is dated 1920. In the early 1920s Shanghai made an oversize M1900 slotted for a shoulder stock and were about 8" long and most had a graduated rear sight.
Shanghai Arsenal began producing the M1900 in 1915 and continued into the 1920s. Pistol 5108 was produced in 1919 and 6896 in 1920. Both of these copies were very close copies of the FN pistol. Chinese sources indicate that M1900 copies were also made by Hanyang, Gongxian (Kung Hsien), Mukden and Taiyuan as well as other arsenals. Although I've seen many other M1900 pistols, none can be identified to these specific Arsenals.
As time past, the design of the Chinese copies evolved. The most common change was to curve the back of the grip for a more comfortable fit for the hand. There are MANY variations of this pistol. M1900s from the WWII period are frequently dated instead of SN'ed. The latest date I have seen was 1945. Some 5 shot models are also known.
All the pistols discussed above are in 32 ACP. There are another set of M1900 copies in 7.63 Mauser which are much harder to find than the 32 ACP pistols. These vary from normal M1900 size but with a beefed up slide to handle the more powerful cartridge to quite large pistols, some slotted for shoulder stocks. Production of these pistols probably date from the 1920s and 1930s. Most are extremely well made, and in fact the fit of the parts is generally better than found on Belgium made pistols.
No shoulder stocks for any of these M1900 copies are known to the Author. There are also a few Chinese M1900 copies in 25 ACP that are quite small, but the Author has not actually examined any of these.
Hope this helps.
Cheers,
Lew