Are GM rearends notoriously not centered?

[fultz1275]

I just installed a new rearend in my 68 chevelle. it is offset to the passanger side by about 1/8". I called DSE to ask them the best way to center the rearend considering im using their upper and lower control arms. They said the GM rears are rarely centered and there is typically less tire clearence on one side verses the other. They said not to worry about getting it perfectly centered. Can anyone confirm this to be the case with GM rearends? Should I expect to have it offset to the passenger side by about an 1/8 inch.