Which bumper?

[Robbo]

I fitted overriders to my HZ, and the overriders had marking's on the them where they mounted to the bar. They were marked like a cutout, so you could snap the pieces out with plier's if the bar had the rubber strip fitted.

[Big Rob]

I do remember finding somewhere in GMH literature that HZ Sandman couldn't be had with the bump strip, but I also have recently seen other literature that contradicts that for HZ. HJ definitely indicates that it was an option. I'm near to certain HX is the same as HJ.

Yep, HX had 'em too if you wanted 'em.