M is roman for 1000///two MM is 2000.... IV is 4 (* V is 5 and with a I before it means 1 less )--- so MMIV means 2004 (and if it was MMVI --it would be 2006 )...in roman numbers ..likely their "token" replica coins from a "seeded" metal detector club hunt done in 2004 or 2006 ..or a horrible prank pulled on you by some jerk...the 2004/2006 roman numbers dating along with a shovel and "detector" within a shield ... means nope its not old ...
the face side does have a sort of byzantine / holy roman empire 1000 ish era type coin look to it however ...still a "fun" find if not a high value one..