The other thing you'll see in hammer and button barrels is the lines the run perpendicular to the bore axis. On a cut (or buttoned for that matter) barrel that has been lapped, you'll just see smooth lap marks that run in the same axis of the bore.
Unless there's a giant goof in the rifling somewhere, I mostly don't even worry about the length of the barrel. Most of what I'm looking at is from the neck forward about 6-8" to monitor fire cracking, throat wear, etc...
On a new barrel, the same probably applies, look for jagged/uneven machining in the throat, rings in the chamber, and in the case of AR's, gas port location (looking for burs mostly).
Looks like a good factory AR-15 barrel.
ETA: I'll echo Steel Head insomuch as I wouldn't get caught up with anything you see unless the barrel doesn't shoot (or it's just outright fugly). Proof is in the pudding. I've scoped a factory rifle that had shallow rifling running all the way back to the neck on one side of the free bore and it still (somehow) hammered.
