https://www.ebay.com/itm/123297285540?ul_noapp=true
https://www.ebay.com/itm/142893266010?ul_noapp=true
https://www.ebay.com/itm/401576626688?ul_noapp=true
https://www.ebay.com/itm/202393187553?ul_noapp=true
Here is a sampling of 1951 Bowman Mantle that are currently available on eBay. The centering is the same. Almost any of theses card could be the missing Mantle. (Not saying they are) a that SGC is pretty nice. You can see that this card will be hard to find IMO. All the Mantles cards are in the grade range. They have pretty much the same centering.
Who ever has the card is more likely not from the area it was taken from. They could be hundreds or thousands of miles away.
Also I don’t think I ever got a receipt for a card I purchased at a show or store.
What if the card shows up? The owner says I paid you for it. I can sell a high priced card at a show then report it stolen. Right?
I mean if I seen one of theses mantles at a show tomorrow I might think HEY that’s the missing Mantle!! Or is it? Should I call the police on the spot and say I think that card could be stolen?
Sorry to be devils adovcate but if it’s cracked out it’s more likely gone. The best move would have been to crack it at the show and sell across the floor and leave.