What K10 says is correct about Chevy and GMC being different. However there is also a difference in early and later ADs. I don't remember where the switch was.

By the way, I can't make out any details in the miniature pictures.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.