It's the common way to do it. Though if you're not careful about the breeder it is easier to get scammed with distance and not having seen the pup in person or maybe their is no pup at all, some people take money for non existent litters. You need to look into responsible breeder even if you will be meeting the litter, as bad breeders lie and could still rip you off. I've not seen a contract like that, I generally see that the pup will be in good general health and free of communicable diseases and then whatever specific genetic disorders. Some I've seen however are not what i see as ideal like only guaranteeing against crippling hip dysplasia or guaranteeing against it for only a small number of months.