Aren`t the new casting numbers for worn out molds the GM numbers GM 16 GM 13 GM 14?
Bottle manufacturers would do same on their molds of mason jars that wore out


~ BD.
"You won't find me in an old folks home" Pioneer Florida Cracker
1958 Apache Stepside
1958 Apache 1/2 ton Panel
1959 Apache 1/2 ton Panel