I have always had my trailer tires balanced when new. This should help with lifetime and may detect tires that are poor quality direct from the factory.
Inspect after balancing, if you can't ask the tech who balanced the tires. If one has an ounce or so and the other has several or very big weights I would be suspicious!
While you are at it, insist on checking the date code before you buy. A few months is ok, Over a year, try to get a different batch.
2017 SLX 195RB
2014 Jeep Grand Cherokee Overland, gas 3.7 V6
Andersen WDH hitch
Dometic Milenco Aero mirrors