Dave, You are indeed correct. Thank you for posting that. Thanks to Tommy also.
It would be interesting to read the 1958 Chevy Truck Shop Manual Supplement. I have a 59 Supplement and it says the only major design change to 1/2T brakes was rear shoes changed from 11 X 1 3/4 to 11 X 2.
1959 Chevy Panel truck Pics below.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn