I think the blue paint (enamel???) tries to imitate turquoise stones: they were very popular in Central Asia (Bukhara, Khiva etc) and somewhat less in Afghanistan (but a good chunk of them are Uzbeks anyway). I am NOT saying it is Uzbeki; perhaps, the owner wanted something reminding him of his native decoration.
Ah, the convenience of being here! We do not have to succumb to the politically correct "he/she" stuff: all weapon owners were "he"