too skinny or awkward puppy?

this is my first basset he’s 13 weeks and when he was weighed 2 wks ago he was 18 lbs. he’s getting the correct food amount recommended on the bag but it worries me his ribs are so prominent (we do see the vet in a week) i read about flanged ribs on bassets while i was researching the breed so i know it could just be that. he is still a crazy puppy full of energy and very sassy but i wanted to see with other basset owners if this is something i should be majorly concerned about aka getting him into the vet sooner!