it may or may not work; I've no knowledge of how the jigoshop plugin works.
I was assuming that you wanted to remove the form from the backend, which removing public=>true should work, but I have no idea how it would affect the plugin
To remove it from the front-end, on that post type (so you could safely ignore the SEO box on that plugin), I'm guessing you could remove the filter hooks that are used. I've not got a list of those, so you will be having to look around to see what needs to stop output on the front-end.