Rear bumper stepside - wrong one?

[Leinhit]

1960 Chevy C10 stepside 2 wheel drive

I received a rear bumper from summit.

Order

Brothers Trucks Bumpers RRB66RW

On their website it says it fits my specific vehicle. However I can't figure out how to get it mounted it doesn't seem to be wide enough to wrap around the rear fenders at all.

*On the box on the outside is printed fits Chevy 55 through 59. Even though summit website listed it as fitting all the way up through 1966, it's says specifically fits my 1960 Chevy C10 stepside.

I'm not finding this the case. Can anyone confirm this is not the right rear bumper? I'm going to have to fight with them to return it I'm sure. And this is the only rear bumper they offered for my truck.

*I want painted, not chrome.

Can anyone supply a specific link to what I do need?

Thank you.