I cannot give you a definitive answer because the calculations behind credit scores are complex, secret, and known only to the mathematicians who wrote them. Plus, the answer varies by person. If you have a fantastic credit score then the slight dip in opening a new account will be inconsequential.
I can say this: The act of opening and then closing a Gap credit card in rapid succession is not a good thing. Unless you already have a dozen or more tradelines, then this Gap credit card will probably not cause you any harm.
See the Bills.com article All About Your FICO Score to learn more about credit scores.
I hope this information helps you Find. Learn & Save.