Subject three stamps appear to be European proof marks, namely first one on left, eventually eagle over N for nitro-powder (?)
A better picture would help, including markings on barrel at ejection port
If I had to pick a country, I'd say East Germany (linked to China via USSR in the Communist world)
Although the bulk of the SMP pistols that were imported came to the USA some were imported by other countries. There used to be a gun shop in Aldershot in the UK that had some SMP pistols. I purchased a few of them. A few were given as gifts at some point and ended up in other European countries.
From the owner in Brno, Czech. I met him on another forum as he is looking for a correct mag for it.
" I finally bought it from Germany. Unfortunately, it has the stamps of the German importer (Frankonia) and German firing proofs."