I have an older R&R cart. The wing bolt underneath the bed

R&R wingbolt

R&R wingbolt 2nd pic

.....the ones that lock the bed for when you're carrying weight.....the ones you use every time you set the cart up or tear it down.

Mine broke. I got these but they're too large. Did they change the size so that the new R&R parts don't fit the older models?

If so, any suggestions on what to use for a replacement. I can still use the bolt but the plastic head broke off. I need to carry a wrench to tighten it.

Mark