Likely to be a difference in the shine/smoothness of the surfaces, as well as color if they are supposed to be the "same" color. That said, such combinations are often done for sports uniforms, and the like--where they are get the same logo/design, but the each player's name is done in vinyl.
I think the main area of concern would be how to cure/press whichever was done last without messing up what was done first. Not something I have done, but I'm sure others have and will chime in.