hi. I think Islamic calendar is not calculated so,we can't just add 622 to find the matching date in the other calendar. it differs around 11 days every year compared to Gregorian. otherwise it would be very easy
The discussed number on the sword has two tips going upward, if it was number 3, it should have three tips. it is carved quite crudely, thats why you think it is a "3" I guess. if it is 1215, it means something like 1799 or 1800 for sure. in 1890s-1900s nobody was making yataghans anymore. Which picture do you mean by "the second"? The second one containing silver inlaid figures, from up to down? Yes some of them are oriental decorations but, you think none of them are Arabic letters?
regards