BudsGunShop.com - Shield plus carry comp

Yes, the Holosun HS407K X2 1x Red 6 MOA Dot Reflex Sight can fit on a Smith & Wesson Shield Plus Carry Comp with an adapter plate:
Adapter plate
You can use an adapter plate to mount the Holosun HS407K X2 on the Shield Plus. Some recommend the DPP Titanium Optic Adapter/Mount Plate, which comes with screws and a tool. However, the screws that come with the adapter plate may be too big for the Shield Plus, so you can use the screws that come with the Holosun HS407K X2 instead.
Shield RMS optic footprint
The Shield Plus is optics ready and can use any optic that fits the Shield RMS optic footprint. This footprint can accommodate up to 80% of micro compact red dot optics on the market.