It is a GREAT idea to have your new birds seen by a vet. A basic health exam can evaluate the condition of the birds, and can be instrumental in identifying any illnesses or signs of malnutrition etc. The pet store is typically not the original source for these birds, and they have likely been purchased from a breeder or another company that purchased them from a breeder. These birds have likely been transported at least once, and even in the best conditions this is incredibly stressful. Stressful situations can weaken the immune system, and predispose the birds to illness. If there is an underlying genetic problem, a weakened immune system can make that condition more obvious.
Establishing a relationship with a vet will be helpful if problems do develop with the birds at a later time. Having a new pet exam will give your vet an idea of where the birds are in terms of health, and this initial exam can be the baseline that future exams are compared to. This will allow you to catch illnesses at an earlier, more easily manageable stage. After the initial exam, it would also be a good idea to have your birds examined by their vet every 6-12 months, even if they are healthy and happy. Your vet might suggest basic blood tests along with the exams, just to make sure everything is going well. Birds are exceptionally skilled at hiding illness, it's instinctual. Often times they can be pretty sick and not show any outward signs. An exam and some blood tests can detect problems in most cases. It's also important to keep in mind that if you see any signs that concern you, or if you think one or both birds is not doing as well as normal, it is best to have them seen by their vet ASAP. A trip to the vet can be stressful, and a sick bird is exceptionally fragile. It is not unusual for a sick bird to die during routine handling at the vets office. I don't want to scare you, but this is the nature of exotic pets and birds.
Please let me know if I can be of further assistance. Good luck with your birds!