Hi Heather. I don't remember, are your boys related? They look like they are.

Another cat I had (RB) had a dull looking coat too. I started feeding him this food called Avoderm. It is a bit pricey, but it helped. It has avacado in it that helps keep the coat in good condition and shiney.
I also feed it to my dog that I have now- it seems to agree with her digestive sytem well (had some problems with some of the others)