I just reviewed the instruction manual online and I don't see how it could be off if you followed the manual. Everything is tab into slot type of build.
I'm pretty sure that when I glued the fuselage doublers together, the right inside doubler shifted forward a little when I clamped them them together. I think this shifted the firewall notch forward enough to move the thrust line to the left.
It could just be an optical delusion
I considered this also, but what effects can I expect if I attempt to take off and the side thrust is angled 3-4 degrees to the left? I've read and been told that that shifting the thrust angle to the right is ok, but to the left may cause some issues.