if you mean the bellows that cover the sliding axle rollers then I wouldn't worry about it too much as I don't have them fitted on mine and I haven't had any issues, however having said that my carrier was a bit of a lash up ! done quickly so I could display it as soon as poss. if I had more time I would do it properly so there you have it, if you are in a hurry then leave them off, if there's no rush then do it right first time. just so long as it's ready for it's debut at next years war and peace
rick