The coins from 1937 till 1941 are struck on a thick planchet and weigh 11 g.
The coins from 1942 and 1943 are struck on a thin planchet and weigh 9.4 g.
My digital caliper isn't working properly anymore, I think I have to change the battery. If I find one I let you know the difference in thickness.
https://en.numista.com/catalogue/pieces2862.html