I realize there is a difference--sometimes--between wild caught fish and commercially tank-raised fish. With respect to water parameters other than temperature, i.e., GH and pH, the tank-raised blue rams should be maintained in water close to what they were raised in; while wild caught fish of this species must be kept in very soft and acidic water.
But when it comes to temperature, there is no give. Warmth which means 82F or higher is mandatory for this species, whether wild or tank-raised. And this is long-term, which brings me to the stores.
Stores expect to keep their fish short-term, they want to sell them. They may have "warmer" tanks for Discus
, rams, and such fish if they are a mainly "fish" store. Or they may have all their tanks running consecutively and maintain a "middle" ground respecting temperature, and GH and pH for that matter. Short term this may be OK, though there is still the unknown factor of what internal damage may have been done. When these fish do not live to their normal lifespan, it is often due to some earlier issue that "left its mark," so to speak.
Whatever a store may do, there is no excuse for the home hobbyist not providing what a fish requires. If one can't do this, then one should not acquire that species. The blue paragraph in my signature block says it.
Additional comment on the number; this is a species that is best in a bonded pair. Males select their females, and bond for life. A group is possible, but not within the confines of a 29g tank. A bonded pair is best here. Or, as someone mentioned, the Bolivian Ram
which works very well alone (one fish), as it is believed to live in nature [see the profile].