Music Man Amps

Hi. I found a nice MM 115 65 combo at a local music store (Music Center USA, really awesome business). I used a photo of it for my profile pic here. I put a hold on it so I don't actually have it yet. My question is, what should the ohm switch be set on? it sounded fantastic but since it's just a flip switch seems too easy to flip it on accident. I have no idea if it's the original speaker or not. It is definitely a 15 inch speaker. Thanks!