Part of me wants to say, you could use anything you want...its your diorama.
The other part, says yes you can use these for 1944. Sticklers for authenticity might give you a hard time about the jackboots since by 1944 alot of troops were wearing the lower boots with gamaschen. Not to say that no one was wearing jack boots in September, just not as prevalent as in 1941. Other than that, based on the box art for that kit, looks like they're wearing camo smocks and all other equipment is relevant for the period.
Have fun.
Mike
"Imagination is the dye that colors our lives"
Marcus Aurellius
A good friend will come and bail you out of jail...but, a true friend will be sitting next to you saying, "Damn...that was fun!"
