Need information about HBT Trousers

[Spatizm]

Hello

I am looking for an early war HBT trouser for my M36 HBT tunic, and this is one of the options i have found. The seller doesnt give any information other than its HBT, so im unsure about some things which i hope to get answers to. These are the images i have. Which model, proudction year, any markings, official production or private purchase etc...? With my limited knowledge it looks like an M39 or M40, but i havent been able to find one that looks exactly the same due to limited resources about the subject that i can find

If anyone knows of any other HBT trousers which are avilable for purchase do let me know

Thanks
(12 files attached)