Absolutely. You have the right to ask and of course the seller has the right to say no. I would get all of the info about the furkid I could -- ask all questions that come to mind and look him over very closely, you are certainly smart enough to rule out the obvious such as a limp or wierd behavior. Then, if you are still intested in the little guy, then have the seller agree to let you take him for a thorough checkup. Your vet should be able to do some simple blood work and take a close look at him for congential problems. Oh boy oh boy, is Eddie gonna get a new little brother?