I think the push bumper was an option on slant-nose and brick-nose trucks. I've never seen a factory push-bumper on an OBS truck, and it seems like it was a rare option on the earlier trucks. The "main" bumper's the same as the non-pushbar bumper; the vertical pieces are separate and could be removed and installed on another slant-nose front bumper if I wanted to (I think the contours are different enough between slant-nose and brick-nose trucks that these vertical pieces wouldn't bolt onto a brick-nose bumper and look "right").
As to the other question...I have plans which will be revealed at a later date
Oh, cool. Didn't know they were separate / bolt on. Hmmm. Thanks for that.
Glad you have a plan, Warden. It's important to have a plan.....