Hehe. Mine had exactly the same glue mark, must have been the same guy on the assembly line. I got it off with some panel wipe. The solvent that you wipe the body down with prior to painting. Smells like dry cleaning fluid - maybe that's what it is - I'm not sure.
thanks Guys sticky mess all off - now I can appreciate the cab without my eye being drawn to the yellow splodge, such a small thing makes such a difference aesthetically