Good eye! That is from Americana pipedream!

As it happens I bought one of those coats from them last summer so I can speak authoritatively about the thickness. It is a normal thickness for a wool coat. Probably in the mid to high 20s in terms of oz/sq yd, similar to a thrifted dkny wool coat that is more modern or my woolrich cruiser jacket. I am quite satisfied with the material and I believe this to be a typical thickness for the material on any greatcoat.