If you mean because of technological advacement, i believe even in the real world people were using muskets to make well into the XIX century. And if i'm not mistaken they first started coming up sometime in the Renaissance, so while i don't doubt they got better over time it still took a major while to move past them to something better (or maybe not, since if we look at history as a whole we really just speedrun shit like crazy in the XX century). So considering fantasy worlds are already unbelievably stagnant by default, plus magic most often making things trivial, i think you could probably throw in early guns in some settings without really upsetting anything too badly.
Of course if it makes sense then that's cool too, like in Thedas where the race/cult staunchly opposed to magic (Qunari) invented gunpowder cause their primary enemy happens to be a society of magic galore. Wish we'd gotten some of that in the games actually, like just one tiny companion with their cool stolen flintlock or some shit.