I think the confusion brought on by the punch caused Jack to behave in an uncharacteristically restrained way. I think he truly doesn't quite know how to read Ennis here and isn't as open as he might have been otherwise. Maybe he should have pushed Ennis a little harder here to stay with him, go off with him, or something... and maybe that's what Ennis is wanting/waiting for Jack to do... since he's still largely relying on Jack leading the way. Still, I think the confusion that started with the "confusing tussle" caused this parting to be much more fraught than it might have been otherwise. But, I agree, that even through this Jack's still trying to demonstrate that he wants to see Ennis again. And, yes his love and desire to keep the shirts certainly show that he's more concerned with those things in the long-run than the passing punch incident.