Often you can encounter statement in the way, that models that use the Holosun K-series footprint use a variation of Shield RMSc footprint. For practical purposes, lets simply say it is not true.

If you will try to install a red dot with Holosun K-series footprint, it will not fit. And there are two reasons for that:

1. The rear Shield RMSc uses four sockets and K-series only two. Thus each mount and adapter with RMSc footprint will have extra pins in the rear. And as a result, any red dot with the Holosun K-series footprint will simply not be able to sit flush on such mounting surface.
2. The Shield RMSc footprint uses deeper sockets in the front. For that reason, even if you somehow remove the rear pins on the mounting solutions, the front pins will still be too high for your red dot with Holosun K-series footprint.

So unless you use a special extra adapter to get from Shield RMSc footprint to Holosun K-series footprint, the footprints are not compatible.