Hxman,
Yes, the prop should touch them. Those are alignment tabs so that the cutouts in the spinner match to the prop. As far as using locktite on the prop, you should NEVER do that. You will want to do that in the future. If the prop is coming off you simply aren't tightening the nut enough. If you are using one of those 4-way wrenchs that you use to remove the glow plug you will never get it tight enough to stay on. Get a good box end wrench for installing the prop nut. Use a rag or put on a glove to hold the prop with as you tighten it so it doesn't slip and cut your hand, and then use the box end wrench to tighten the nut. Don't worry about stripping it out because both the nut and the shaft are made out of steel and will handle it.

Ken