I think the 1/4-20 bolts you are reffering to are hold the cover on. After removing these cover bolts you install two larger ones to remove cover, as shown in Bowhunters 585 cam install pics. Correct me if I am wrong.The service manual calls out two bolt sizes 1/4-20 x 1-1/2" and 1/4-20 x 1-1/4"