No Problemo Pal...I think the last lot are at the end of RF. Go to the very last screen before Stock Yards,chuck the grenade to your right to kill the sleeping Slig. Now run and jump onto the platform where you threw the grenade and roll to the right...Here is a secret bit,pass through the drills to the next screen!
Also,Mudokons are hidden down trap floors sometimes,and press down,when a barrel is in the foreground.
Hope That Helps