"Six full ounces" is at the bottom

[Dmar1911]

I need help trying to figure out this Dr pepper bottle I found. It looks great no cracks but it readseems at the bottom of the bottle "six full ounces" on the bottom of the bottle here are two pics I have. Any help is greatly appreciated. Thank you.

 

[sunrunner]

looks like 1960s . depending on were your from . I would say short run .( NO PUN INTENDED ).