He is TOO cute, Liz! I bet you have a grand time out with him 😀
With the amount of time that you and he spend out and about and the energy he exudes, he should be reasonably fit or better but that does not always mean in proper weight by default. Put your hands on him, head to toe to be sure. Is he squishy or solid? If solid, is it bone hard or flesh/muscle firm? Adjust diet if/as needed.
Sure there's right and wrong but mostly there's just a whole lotta different.