Im in the same exact boat as you XANGCRIS, I didnt get the chrome but I have the flaming one for no reason. I think it may have something to do with if you where connected to LIVE when you got the achievement. Look back at your gears 1 achievements and if
it doesnt tell you the date you unlocked it, thats probably why.
Hopefully this will be patched soon. I want my goddamn chrome retro lancer epic!
The flaming Retro Lancer was accidentally unlocked for people who didn't even play in the Gears of War 3 beta. They fixed it later. The option of chosing the flaming skin was removed from my options list a while back, but as it was selected as flaming before,
it was seen as flaming unless I changed to another skin. At that point I wouldn't be able to change it back to the flaming skin again.