I'm a noob and was wondering if there is any rule against targeting the same hull zone of a ship multiple times with the same ship? For instance can I attack the front hull zone of my opponents ship if I attack once from my front and once from my side hull zone? I know with the upgrade card that lets you attack twice from the same hull zone you can not attack the same ship or squadron twice.

You can not use the same hull zone to attack from twice unless you have that upgrade card (Gunnery Teams).

So you may attack with your front hull at a ship and then if another hull zone has Arc to attack and Line of Sight it may also the same ship you did initially and even the same hull zone.

Simply, yes. You can attack their front with your front, and if you happen to have a side shot on their front too then you can do that for your second attack.

The reason gunnary team says that you cannot target the same hull zone, is because it is a challenge to get two of your firing arcs on the one target facing, and it isnt trying to negate that.