I think it's a safe assumption that they'll be worth more as collectibles than as burgers.
Consider the following factoids in the context of exchange rates and PPP. In other words, the ratio of foreign customers to domestic is probably far greater than foreign revenue to domestic revenue.
Factoids:
* Roughly 1.5 million Big Macs sold each day in the U.S. alone. https://expandedramblings.com/index.php/mcdonalds-statistics...
* U.S. accounts for less than half of global revenues. See https://www.statista.com/topics/1444/mcdonalds/ and https://www.statista.com/statistics/219453/revenue-of-the-mc...
* They serve over 60 million customers globally each day. http://www.thefiscaltimes.com/Articles/2012/04/30/13-Disturb...