If you purchase from KL/AF websites, DL TATL flights will always be AF/KL marketed when involving connecting itins from what I've seen. The only times I've seen DL marketing and fares when purchasing from KL/AF websites is on itins that are both non-stop and DL TATL metal. FCM offers are only offered on flights that are both DL metal and DL marketed (and there's no guarantees you will see any just because they qualify. Further the mileage pricing is not fixed and simply based on the cash FCM offer at 1 CPM). If you are talking about MUA upgrades, they are now only available on DL metal on ex-UK, ex-France, and ex-Ghana fliights and you also need to purchase an eligible fare class (which has always been the case).