Why don't you take it apart and see what the issue is? If the blade is tight, then there really isn't anything in the that CAN rattle other than the bearings.
Take it apart, noticing how everything came apart. Take pictures if you have to so you can see how it goes together. Very simple to do.
Then lube the bearings as you put it back together. Use something heavier than WD40, a little oil from the garage if that is all you have. Grease would be better if you have that. If you have no oil or grease, try Vaseline. A little goes a long way with all of them.
The rattle should go away. If not, then you can send it back if you have to, but A) you probably will fix the problem and B) you will know your knife much better as you know what it looks like inside.
Locktite will not fix the issue. Locktite is basically a glue and if you put it on the bearings all you'll do is glue them to the carrier they ride in and then they will no longer roll, thus, your knife will not open. Fasten that thing back together and you'll have a much bigger problem.
Main thing is to make sure you have the correct size Torx bits for the screws, make sure they are just snug enough to fit so that you do not round off the inside corners of the screws when you put it back together.
Tighten the big pivot down just enough that you do not have any blade play side to side when open, but not so tight that it is hard to open. The perfect tightness you'll soon discover, no play but opens ok.
If the blade is not centered, and has a bigger gap on one side than the other, loosen the pivot screw and the other screws a little bit, and push and hold the blade against the side of the handle that has the bigger gap as you slowly tighten the pivot screw again. That should center it up. Tighten up the big pivot first, find that "sweet spot" again, then tighten up the smaller screws.
And there you go! Much faster than sending it back to Oregon.
