Are there any rule differences between the NHL and AHL?

The AHL has 5 skaters each in the shootout rather than three.

hmm there are probably others, but don't immediately come to mind.

add- 16.1 Minor Penalty - For a minor penalty, any player, other than a goalkeeper, shall be ruled off the ice for two (2) minutes during which time no substitute shall be permitted. During the Regular Season, for a minor penalty occurring in overtime the player will be ruled off the ice for one (1) minute. If a minor penalty occurring in regulation has not expired prior to the start of overtime, the player will serve half of the time remaining on the penalty.

To add to what Jay said, when they are considering rule changes in the NHL, often times they will experiment them in the AHL.....so, there is a good possibility the NHL is looking at going to 5 shooters.

I was at an AHL game last night, and all of the players had on visors, so I assume they made it mandatory to wear a visor in the AHL.

That's just a guess, I don't know for a fact.