I label quilts when they are finished and include the title, my name, location, and completion date. I consider it the signature on my work, like signing and dating any other work of art. If it's made specifically as a gift, I include the recipients name and the occasion.
If I were to gift it later on, I think I'd probably add a second label with those details so it would have both a 'quilt label' and a 'gift label'. Dating a quilt years after completion because you're giving it to someone just seems kind of deceptive to me.