Dropped. This kind of minor damage is more cosmetic than functional on a snub, but on a rifle it would be a "no buy" for me... This one would be more difficult to re-crown than most because the muzzle is level with the cylinder retention.
I'd like to suggest that if the damage bothers you (and it would bother my OCD for sure!) you could probably fix that relatively easily with a fine file or wet-dry sandpaper and a bottle of bluing. Just work slowly and carefully. Now, there won't be a lot of agreement with that, because the common wisdom is to accept these signs of wear and tear as part of the gun's "character." I respectfully disagree. Either way, it's a nice little gun and I hope you enjoy it for years to come.
I could do a little polish, but it really isn’t all that noticeable unless the light and angle is right. Probably just leave it as is for now. I’ve repaired similar damage, but it was more pronounced.
Sometimes you just never know... I have a Remington Rolling Block in 50-70 (New York State Militia issue) with about a half inch of barrel pitting right at the crown of the muzzle. You’d think it would benefit from counterboring, but, as is, it shoots extremely accurate. So why mess with it?