Something to worry about?

 Keeper does the same thing!! I dont worry about it. He isnt growling,barking,lunging to get to other dogs. I just say "keep walking" and a gentle tug on the leash and we go on. I dont let him greet the dogs out here. Dont want no unwanted dogs thinking since they know my dogs they can come in my yard as they please. Keeper does it too if he hears something in the woods or sees Oscar the cat and they are friends.

 That is relieving to hear haha. I mean I can tell he isn't being aggressive, but I just want to make sure it won't lead to that either.

I wouldn't make a big deal of it.  THis behavior alone I don't think means a whole lot.  My dogs do this when playing with each other and Nikon does it when he gets really excited (playing fetch, tugging, etc).  If Simba is a little unsure of himself, I'd make dog meetings positive and quick.

 Okay, thank you. :)

Piloerection can be a sign of arousal, anxiety, ambivalence.  While it's not telling on its own, you always need to read the dog's other signals to see if you should leave things alone or intervene.  There's a great book on body language by Barbara Leonard Handelman if you want to know more...

 If hackles are up on the shoulders only, then I'm on very high alert. If hackles are up elsewhere on the body, I'm on low-medium alert.

 Emma's entire back and tail would POOF when she was arounsed, about anything. She was an extremely reactive dog, and it was always amusing to see the little things that made her POOF.