You already bought the replacement lid. I would just use the new taco lid. It will look much better and more enjoyment cooking on is what I am thinking. I had a similar situation with my Gen 2 Grass Green. I did not like the porcelain loss around where I pop the dent so I got the replacement lid. Up to you if you want to save the old lid, but for me I pulled off the lid handle assy and used it for other project.
I would prefer the correct gen lid, but given the choice... a brand new taco lid for me. Most people don't care or know which Gen. anyways. So, no real value added or lost either way. I am thinking you would get better resale value with a new lid.