Here I will post some buckles to compare with.
The first one with the belt is early one and was taken by German veteran as a trophee in the first days of the war.
The second with KiИB markings are late war and early postwar buckle. Third is circa late 40's- 50's made by Leningrad Military District, and by the look is similar to the modern ( 1970-80's).
First prewar one is very nice quality made, and H and C is similar and solid as in the officers buckle of the same period.
Take a look and comapre yours