107347y is the serial number and should match on the scope, call Leupold to verify
Leupold employs serial number tracking for all its riflescopes, so if a customer finds a scope that is suspect, he or she can simply write down the serial number and call 1-800-LEUPOLD to confirm if it is indeed authentic.
It's what's in the box that needs to be verified. You'll have to see the scope itself to look for fake characteristics. If you can't get the seller to open the box, see if they can produce a receipt tying the scope purchase to a reputable dealer.
Your Thread Title really threw me . I never saw or owned a ' 56mm ' . only ( 8-25x 50mm Obj.) in the ( 8-25 Mk4 ) model's you are talking about & ( don't think ) Leupold ever produced a 56mm obj. in that model .
But Pic. of the box says it all & it looks real/factory even before you called Leu. for reassurance .
At 1st glance at your Thread Title & the misprint of 56mm . I was screaming FAKE to myself .