When there is a new job, weapons are not usually made for them except from the level they start at and some of them after that are avoided such as the relic weapons. Because the level 80 extremes came out after gunbreaker and dancer released, there are level 80 crafted extreme weapons for them.
GARO is an old event that was designed for the jobs that existed when it came out and it wasn't regularly updated with the new jobs, so we are lucky for any updates now. I don't know if there are any other GARO characters to inspire gear for the new jobs, so reskins might have been the only option.
It would be nice to have glowing weapons sooner for new jobs, but the selection is always limited to begin with and I don't expect the developers to go back through 90 levels worth of dungeon, extreme, savage, crafted and tomestone weapons and make versions of them for the new jobs. That would be well over 100 weapons for each of them.