So my question is this, I know you can keep the crown and not complete the quest, but if you do give it to Tullius or Ulfric will you be able to get it back later? Like is it in a display or on Ulfric's head or something? Currently my quest for it is bugged anyway and Korvanjund is unaccessible but I find the crown to be the best dragonbone helmet and would like it even after the main quest or the rebellion is completed.

No it is not, sorry, the crown disappears after you deliver it

If you can use a mod, or if your on pc use console commands.

No, unfortunately once you give it up it's gone for good.

Edit: Hah, three posts basically saying the same thing posted at the exact same time.

This is more of a simple question than a real discussion

Yeah thats what i was afraid of, though thanks for the quick resolution for my conundrum haha

Although I keep hearing of changing save data (im on the 360) with some sort of program, is it possible to do so to gain the crown back?

If you are on Pc, yes, if not, well, I never heard of anything like that.