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Neither gun has any significant collector advantage over the other. In ten or fifteen years they will have appreciated in value comparably.
Much of the purchase advice will be based on personal preference for one caliber over the other.
These are two of my favorite calibers to shoot. Choosing just one would be hard for me. As suggested, I would buy both if possible. If I did not have enough cash to buy both, I would suggest a Lay-A-Way deal. Say 50% of the price up front and then 10% a month for 5 months. I know we live in a world of instant gratification, but Lay-A-Way accounted for 60% of the high end firearms I acquired in my youth. Patience is the key.
If the seller wont go for that, you appear to have no real preference and you only plan on shooting it once (ammunition availability is a non-issue), I would say take a good look at both and see if one has a little something extra that catches your eye and buy that one. Perhaps a little better blue, nicer grain n the wood, better balance in the hand, etc.