Looking for opinions on a repro rear bumper

[buds56]

I bought a new rear bumper in July for my GMC, new brackets also.

I'm not happy with it, the center is high and each end bows down gradually.

My truck is no show truck but I think this is fairly bad. It bolts on fine, I did try shimming and spent a fair amount of time moving and adjusting.

My thought is it was banded too tight in the center when shipped and a group of them look like this

The vendor originally said they would replace it, but I just got a call from them and they said they all look like this.

Here is a pic

picture upload sites

Has anyone had the same problem?
I have bought these in the past and had no problems and the thought of spending another $300 is not appealing.

If you look from the side, it's straight, in the pic it looks like a twist on the right side.

Are they all like this now?

Thanks