I found a Trunk Lift Support for my 2005 GEM at LiftSupportDepot.com but the shipping they wanted to ship just 1 was close to the price of the Lift Support so I bought 2 to get free shipping. I have the 2nd one listed on EBay with a lot less from shipping than they wanted. Here’s the listing.
https://www.ebay.com/itm/203560087407
I sold it within a couple days. The one I bought had slightly longer metal lugs than the original but they both unscrew on the original and new one and are a perfect fit