Your grease will work just fine. I used similar stuff before I got some lubriplate (brownells). I also found that a small water coloring paint brush works good to apply it. Except of course for the roller. You've got to force it in there.
As has been said, your rifle is not glass bedded or glued so you will have zero problems with field stripping it. It's not totally neccesary, but the only negative you will have probably is that your POI may shift a little after reassembly. And it may take a few shots to settle the action back into the stock.
Remember, it is after all a battle rifle. Now if you really want to start tinkering, talk to Kraig and some others on here and visit the m14 forum. There are a few very simple and cheap things you can do to your rifle like shimming the sides of the receiver with card stock and shimming the gas cylinder that can really improve accuracy.