Copy? I Would Really Appreciate Your Thoughts!

I'm guessing the +/- 1% diameter difference is well within tolerance but I'll defer to the experts.

I note that this coin has some significant value in VF and better grades.
Have a look at the edge for some sort of tooling to reduce the diameter slightly. If genuine, that will reduce it's value significantly.

Modern struck coins (of which this in an example), are constricted within a collar during the striking process.
Unless there is a variation in the collar diameter, there should be almost no toleration at all for coin diameter.

That leads to the possibility for coin forgery or coin fakery.
If it is high quality pressure cast, the reduction in diameter is quite believable due to metal shrinkage as the metal cools.
Centrifugal pressure casting can and does yield high quality fakes, with all details rendered quite accurately, and almost total absence of casting bubbles.

I am not saying that this coin IS fake, but that possibility should be considered seriously.

XRF testing against known genuine example should help to confirm, either way.

It's a little smaller than a quarter. But I found it going through a bunch of old foreign coins that I put it away. I remember getting it in the first grade and I'm 44 years old now. Just brought back memories of a school project I used it for. The only marking on it is a small M on it. Just was curious. Thank you for your help. I just got back into collecting again. I was a Marine for 4 years and I have accumulated alot of coins from all the places I've been. Alot of the coins are European pre Euro. Just brings back a bunch of great memories. Even found old Bridge tokens I squirreled away.