I use mounts for smaller seekers. Yes, mounts work for seekers!
You just have to install them. I have a "Reduced Seeker" mount that makes 1/2 size missile components firing 1/2 damage missiles. This is indeed useful for over-whelming enemy defenses. But, for all the ranting about the AI being stupid it's at least smart enough to use a mount whenever it can! It can be a real problem to wade through the clouds of WP fired missiles when you want to take out an AI defended planet. But, most will think that's a good thing.