Thanks Kubur. I was hoping that (maybe) your gun had some proof marks, but these are not.
As a guess only, I suspect that they are numbers which were on the parts before they were put together by one of the many "backyard" makers in the Khyber. One of the links posted (here or on the Jezail thread) mentions the "collection" of parts which were then assembled into complete guns.
Not in anyway criticising, but you would do well to dis-assemble your gun and get rid of the rust under the barrel. It looks quite serious. Just a suggestion.........
:)
Stu

I refer readers to the use here of the video seen at~

https://www.bing.com/videos/search?q...51&FORM=WRVORC

~ which gives an excellent feeling of standing behind this weapon and the effect of the smoke pushed out from the 577 black powder cartridge ...This actually often obscured the targets .. As the presenter says this weapon went all over the planet and in the hands of a trained shot was devastating...and could be fired at up to 23 rounds a minute...incredible for a single shot, hand fed weapon.