Yes, those are what I called wings. Your ability to cut them with the sight installed will depend on your tool and ingenuity. Use a flashlight and observe which part of the base assembly is pushing on them to deploy the sight. You will cut them so that the sight is deployed by just a smidgen of the wing tab. What you are doing is reducing the size of the engagement with the sight base so that you can push on the sight and cause the tabs to slip the base.
It won’t be floppy. But if you remove too much of the tabs, it won’t auto deploy. I have a small set of precision side cutters and I was able to cut the tabs with the sight installed. I hit the mark on my first try so my sight autodeployed but could be pushed forward if I wanted it out of the way.
And, the M*CARBO notch sight is the tallest rear sight offered. It is significantly taller and some folks have reported needing a taller front sight post to create a sight picture they liked. The notch sight works fine with the factory post, but if you want to line the centerpost up on the same plane as the side posts, you will probably want to swap in a taller front post. The only Sub I’ve fired using the notch sight was zero’d with the top of the centerpost set halfway up the notch site posts.
Back to the sight mod … if you are uncomfortable with the operation, order one or more replacements from Kel Tec. KT prices it appropriately for a piece of plastic so your only really risking your time.