Regarding the chinstraps on your helmet, I’m pretty sure OD7 ones were around late war so would be correct for your impression. I couldn’t tell from the video whether or not the buckle had a raised bar where the chinstrap is attached (i.e. raised bar means it looks 3D), I’m pretty sure late war ones were a flat stamped buckle like the post war ones but without the round knob attachment. But no one’s going to notice that at an event or even in a video so I wouldn’t worry about it.
Regarding the chinstraps on your helmet, I’m pretty sure OD7 ones were around late war so would be correct for your impression. I couldn’t tell from the video whether or not the buckle had a raised bar where the chinstrap is attached (i.e. raised bar means it looks 3D), I’m pretty sure late war ones were a flat stamped buckle like the post war ones but without the round knob attachment. But no one’s going to notice that at an event or even in a video so I wouldn’t worry about it.