1746 Proof Half Crown bought as a " replica "

As I was sifting through a bunch of nothing coins at a Sunday flea market the vendor told me that there was a bunch of new and neat stuff. After not getting anywhere and ready to give up I came across a 1746 proof half crown marked " imitation ". I paid the $4.00 and subsequently certified the rarity and is now in a proof - 61 holder ! Right place at the right time.