I have just bought a second hand Miroku, but it doesn't have any model number.
It appears to be exactly the same as the below I've just found online:
Can anyone tell me anything about the Mk60 Special? It doesn't appear to be like any other Miroku I've seen, with no engraving and the barrels are finished in matte black instead of the usual deep blueing.
According the codes on the 28" barrels, the top has full choke, and the lower is half choke. Length of pull is 14.5".
The serial number ends NP, so I'm told it is a 1998 gun.