The shape and patterns of their bars don't typically change too much. Sothose will likely remain similar similar in pattern as he grows. The transformation of their colors are a different story. There is absolutley now way to tell what a 4 month old will look like a year from now. You can look at the sire and the sire of the dame to predict what your chameleon's colors might look like.
This is why when you buy a chameleon from a breeder they also advertise the sire and dames name ( the mom and dad) most times they will list the name of the moms father because you can't always tell what coloring you will get from a female without knowing her lineage.. There is no other way to predict what they will look like.