OP wrote:
Front wheel cap protection
I'm assuming that your title is what you're asking about though the text of your question seems to be referring to the body part (front cap, not the front axles wheel cap)
Adding protection to dust caps on wheels is a good idea whether in Alaska or any place else where you travel on gravel. Probably the BEST protection you can get is to cover the wheel dust caps with solid hub caps. If you can't do that then you're pretty much leaving it to chance. When rocks hit the dust covers is WILL remove them. I ended up traveling almost 600 miles with no dust cap on my trailer because it was knocked off by rocks.
I suppose if you want to grind off the hubs enough to remove ALL grease you might help some by duct taping around the edges but probably won't survive much wet weather.
Good luck / Skip