Gundam Heavyarms Kai manga version

This is kinda bothering me a lot. I’ve just recently finished reading Gundam Wing manga. I don’t know why the Gundam Heavyarms kai in TV series or an old 1/144 scale HG does not have the beam cannon on the right side area of Gundam Heavyarms kai. While in the Manga it shows the beam cannon similar to the FA-78-1 Gundam Full Armor Type.
The robot tamashi line of Gundam Heavyarms Kai have an extra gatling gun which can represent the beam cannon, but would be better if they add the beam cannon. It would look even more bad a$$.

Here is the pic show in the manga. In the manga it actually fired the beam cannon. Not show in TV or any bandai kits though.

Wow it’s weird I edited this tread but somehow it turned into a new tread. Mods please delete the other tread.