There are 029 and 029 super filters, and there are 029 super and MS290 filters.
One has a hole inle the back for the compensating carb, the other doesn't.
Can't you just cut open the filter thats closed off in place of the other? It's just molded plastic, the nipple is even there already, just needs opened up.
-Ralph, who has 2 bags of new closed hole filters