Please keep us informed if you find anything out,CC. I agree that it doesn't appear that either piece has had the hilt replaced. Likewise, I don't think a collector would arbitrarily stamp an item in their collection, as it might affect the value. No curator in his/her right mind would do so. Leaving the question open as to whether these are government and/or private purchase pieces. You are both lucky gents to own them, though. I'd love to have them for my collection. Say, maybe you should send them my way so I can do some of my own...research!
BTW, thanks for posting these. It's good to see a naval item or two now and again.