I believe this may be a Bundeswehr/Luftwaffe Koppel for the "Einigkeit, Recht und Freiheit" Buckle...
no that can not be because they are 52mm wide !
This belt is typical 45 mm wide !
I hold a similar belt with black felt on inside . It comes with a SS nickel silver buckle and coms out from a veteran from Leibstandarte Adolf Hitler .
But never seen bevor one with dark blue felt ........