mostly they were used MP-82 bakelite fuzes.
This is field knoledge M8owner but I will look for documentation for you.
I've never met 45mm HE shells with M1 fuzes so this is weirdI've seen only KTM-1, KTM-3 or M50.
I have a Finnish manual, dated 1941. The document says that fuzes were in use: M-50, M-1, MP.
The box is original for 50mm mortars. They also had a wooden box for 14 shells, however I have never seen a wooden box.