I bought a Bug Wasp and a WB820 separately.  the mount for the 820 has the curves to sit on the frame rails but it won’t fit between these circular tabs that are attached to the chassis. the chassis came with a mount that bolts to the 4 tabs but then the 820 base only tests on a narrow strip of cast aluminum with 2 bolts. this can’t be right or sufficient in my opinion. is there another part I need to buy or ??? TIA