I've asked before, but I'm still confused. I had a bumper on the rear of my '53 3100 that was curved, and I figure it's actually a front bumper. It isn't as rounded as the stock '53 rear bumper, and it fits the front bumper brackets just right. But a stock rear bumper doesn't line up with the rear bumper brackets. What's going on here? Did '54 s or 1st 55's have a different (more like the front) bumper??