A friend, who has been living in Japan for a few years, brought me a few old coins she found in an antique shop over there. Among them is this, which appears to be an old 4 Mon. It matches this coin in Numista: N#147023
Diameter: 26.6mm
Weight: 3.31g
Can any if the specialists here tell me whether this is real or a replica?
Thank you very much in advance!

