Yes, an Allen Wrench is the correct tool. You may need a longer Allen Wrench to get enough torque on the bolt. Or even a socket Allen tool which can be used with socket wrench to get more torque. Those tend to be kind of expensive for a singe use kind of item. If you are having to apply a lot of torque to loosen the bolt you want to make sure it is fitting very well to avoid stripping the bolt head.
Sorry to hear about the stipped bolts. When Allen bolts get stripped it can be the worst. The stripping tends to happen at the top of the hole. You might be able to get the bolts to move by getting a socket Allen wrench and hammering it down into the hole before attaching the socket wrench. Then attach the socket wrench and very very carefully increasing pressure to turn it. Can you tell I've done this myself? Best of luck. I believe the mounting kit has new bolts, so hopefully you can get the others out and then put in the fresh ones.
I did the exact same thing. I tried to use an Allen wrench, but those bolts have locktite on them. A hex socket attached to a socket wrench did the trick. I stripped one of the bolts so bad, it was hopeless. SOOO...off to the auto parts store for an "easy out" kit. The kit comes with a drill bit and another bit. I drilled a hole with the drill bit, hammered in the other bit, then used a socket on the second bit to remove the bolt.
I had the exact problem. I stripped the first bolt. I took it to my dealer who proceeded to strip the next three. Once they got them out, they told me that the specification called for blue loctite and the factory put red loctite on them. They remarked that they would see a whole bunch more of this in their future. You didn't do anything wrong.