I just got a superstar 40 arf, I've been putting it together as I find time. Yesterday I noticed that the vertical stab looked a little funny mounted on the plane (unglued). So I took it off and laid it on a flat surface and it seemes to be warped a little bit, is this normal? when it lies flat there is a gap between the table and the vstab about 2mm long (this is measured at the greatest point..in the center). I laid it under some books overnight to see if it would flatten out but it did not. Is this nothing to worry about or should I try returning the vstab? Thanks