A/B series swingarm tank anti roll rubbers

[ANDY HIGHAM]

Something that has been mashing my brain for a while now.
The anti roll rubbers fitted in the frame do not touch the tank. The distance across the rubbers is 59mm, the width of the tank tunnel is 67mm which leaves a 4mm gap each side.
The "head" of the rubbers is 11mm thick. I rang another supplier, theirs are the same. Am I missing something? I don't recollect having this problem with my A10 but that was 20 years ago and I have been drunk once or twice since then. ;-)