"Was Iron Slug’s charge changed since the gunner update?"

It was changed massively in the gunner update. To my recollection it has not been changed since then.

Your "side note" is a better use for this thread. And price checks belong in the Bazaar forum, where you will find better luck. So consider moving this thread there (by editing the original post, choosing the Bazaar forum, and not leaving a shadow copy). Best wishes.