US M1 cloth helmet covers

Look at this video on You Tube. It's a 1959 Pathfinder training film. What caught my eye was the cloth helmet covers. I've looked at a lot of M1 helmet pictures, but I've not seen this one yet. Looks like just a flat piece of OD cloth folded to fit. Were they issue or improvised?

1959 USA Military: Army Pathfinder Team Training Film 250207-06 | Footage Farm - YouTube

I've looked at this sort of thing before. I think they were just trying to figure it out then. This could just be canvas, I know I've seen sandbags too.

From what I've seen this is spot on.