That's an end link to the rear anti-sway bar. No, you haven't hurt anything by not running it... in fact, you'll get better articulation in the suspension when you take it out on the trails with the swaybar unhooked.
No clue as to the part number you need, but I'd measure the length of the one you have, and find a matching length set in a parts store and replace both for less than you'll pay for the dealer part.
Yeah, I can do that. Just go stand over there... no, behind that wall. You may wanna duck, too.
2000 WS6 with a lid, 0 hp, 0 tq to the front wheels. GONE!!!
1985 CJ-7, cammed 258, 4-bbl, headers, duals, 33s, 4.56s, Detroit Locker rear, TrueTrac front, ready to play. GONE!!!