There have been some early Spanish silver and gold coins found in a couple of spots on the beaches around Corolla over the years so it's not unheard of to find one of these. But there's something about yours that doesn't look quite right although it could be the result of long-term exposure to a salt water environment.
I picked one up on fort Myers Florida two years ago I was pumped for days untill I got all the crust off it and saw COPY on it my hart sunk but it make for a great story to friends I believe mine to be silver
The first thing I notice of it is that it's not silver. Yes, cobs can be bronze, but no real bronze cob/maravedi ever looked like that. I thinks it's a piece of trickery.
Darn! Your coin sure does have the word "copy" on it, but even so it is a fun find and worth a post. Don't be disappointed. It's all fun, and you are in a great area for finding older treasures be it coins or relics. Hang around this forum and read what the old guys have to go through to find good stuff. Besides, you can learn some tricks off of 'em.
Best of Luck,
Phil