Those batteries are manufactured by Marathon (Exide), and are commonly used in mobile cell site DC systems.
They sure as beans are either second hand - the spoils of a battery change out project. Or, stolen - as the price is way too cheap.
The battery will either have a date code stamped on it, or the serial number will contain a date code.
I obviously can't speak for all Telcos, but in our case every one of our batteries can be traced by it's serial number - data centre, purchase and install date.