Yes. Companions tend to have enough skill about a weapon depending their tagged skills. You can check in the companions section of this wiki which tagged skills they have. Also they level with your level so when you are already around level 22 their tagged skills will be 100. EG: Boone when you reach level 22 will have 100 guns and 7 strenght. This can be raised if you give him some armor/headwear that raises his stats, like power armor, thus increasing his strength. They suffer armor penalties too, T-45d power armor lowers AGL which would make his guns skill less and do less damage with guns.
Thanks, that was very helpful!