Mine was off too, added a thin washer to the bracket and now it's dead on

 

I had the same problem myself. It was a bunch of loosen, tighten, etc. (both brackets and pipes) until I got them as close as possible.

 

I just might have been one of the lucky guys. Mine installed exactly centered.

Now, I did have to spend some time to make sure the tips were exactly the same height from the ground. That took a friend holding the left pipe upward while I tightened the rearmost pipe clamp and the fishtail mounting bolts.

 

my samson fishys came with a bent bracket. it was warped, kind o twisted....i sent it back to them and the rep confirmed it was bad. the new one she sent me was also a little bit off. so what i did was go to ole faithful (The Home Depot) and bought some washers. i ended up putting 2 washers inbetween one of the mounting bolts. (between rear bracket hole and frame). this addition brought the pipe in and trued it up nice.

simple fix.

but ....im still wondering why. maybe they had a bad batch of mounting brackets?

 

I guess I got lucky with my Samson Fishtails, no problems with not being centered. Or maybe my bike is like some of the other posts have said, the rest of the bike is so out of alignment the pipes look straight.