No. Golf cart 6 volt batteries are deep cycle. Any battery that posts a cca rating is not deep cycle. Not only are 6 volt golf cart batteries true deep cycle batteries with thicker plates but they are much easier to handle that 8D's.
Why are you set on AGM batteries?
AGM Batteries - Making The Choice - SailboatOwners.com
Why are you set on AGM batteries?
AGM Batteries - Making The Choice - SailboatOwners.com