As Willys45 said, "It's your jeep and your money".
With that being said and with all due respect, if it were mine I would not alter that jeep's spring configuration (or tire size) unless it is something the military would have done. I would try to keep it's configuration as orignal as possible, particularly with the history you have on this particular jeep - you got it from your wife's grandfather who got right out of the service. That's some provenance/history that a lot of us here only wish we had on our MV's. Modifying an historic MV for practicality, safety, or necessity (don't have the $$, can't find correct parts, etc.) is one thing and many do that while still maintaining most of the historic configuration of their vehicle. As was pointed out, if your springs are bad you can get great reproduction springs quite easily that will preserve the original configuration of your jeep. As another poster suggested, if you want a jeep to jack up, buy a common Wrangler, not your rare-with-clear-ownership-lineage flat fender piece of WWII history.
I feel the same way about antique cars. Taking a '57 Chevy today and cutting it up to turn it into a hot rod today is a no-no in my book. They did that to them back when they were common and cheap. Taking one that is still in original condition or can be restored to original condition, and "rodding" it out often times obliterates irreversibly one more of the pieces of history that are getting fewer in number every day. There are some who would argue that doing this is simply restoring a piece of history from the '60s or '70s - the hot rods that the piston heads built back then. So I guess there could be some justification there. I don't think that argument holds for MVs though.
My perspective is that if an historic MV is altered from it's original configuration because it "looks cool" it is no longer an historic MV but just another jazzed up 4-wheeler. May as well change it from OD to chrome too (we've all seen that one, haven't we?
Just my $.02. No matter what you do, enjoy your jeep!