Yup. Isamu was shooting at the Ghost after the dogfight(both movie and OVA versions.) Also Guld was the more reckless of the two when it came to firing off weaponry. More missiles, more gunpods shots, more property damage...etc. If you re-watch that episode Isamu was on Gulds six when they were heading into the city and during part of the city chase. Why didn't he shoot down Guld?
For the most part Isamu was flying defensive against Guld. He was there to fight the Ghost, not Guld. Oh, and Isamu losing his gunpod and head laser was because of debris from when Guld crashed through that building. I very much doubt that that effect was calculated by Guld.
That sounds right. As I watched it, Guld was the one firing dozens of missiles. And they were pretty much even with the whole "knocking off fast-pack" thing. Guld may have shot the headlaser off the 19, but did land one nasty double fisted punch on the 21, Daedalus Attack style.