I never liked the 15 I much prefer the 12 and the 12/15 I also had the MK III in left hand they all shot extremely wellFirst came the 12, the 15, then the 12/15. They were followed by the heavy true target Internationals.
That is a Model 12 pictured above. It has a rear barrel sight in addition to the fold-down removable aperture sight. It is also distinguished by the front sling eye attached to the barrel, a straight grip and smaller buttstock, more like it's model predecessors.
alas I no longer have any .I still have a new aperture rear sight for the 12 somewhere in my parts bin.