The sticker indicates the manufacture date, ...
The date code is branded into the case, any good distributor will warranty on date code, no receipt needed.
I have developed a good relationship with the local Interstate distributor. They have 4 warehouses, 3 in Mesa and 1 in N Scottsdale, they go through 4-5 semi loads of batteries a week. Have a meeting with the owner on Tuesday, will propose a CSC account.
Interstate is partnered with Optima, so stocks, sells, services them. They have exchanged at least two for club members, who had problems with the store where they bought them.
That said, the only way an Optima would be in my rig is if I needed to mount it sideways or in the passenger compartment or weight was a huge issue, like a race car. At one time all of my city, emergency fleet customers ran Optima batteries, now none do, have not proven to be suitable for mission critical use. All of them went back to Interstate.
In talking to the pros, the AGM batteries don't have the life in AZ that a good lead acid does. Why pay twice the price for something that is less durable, reliable?
My rig came with a regular Interstate, looked like it was for a Honda, tiny, had a spacer under it. When it died a couple of years ago, the date code said it was 10yrs old. Replaced it with a group 27F Megatron, good to go, likely much more battery than the rig needs.