It's just two studs that hold that housing on with a O ring under it to seal. I would go to Ford and see if they sell that gasket without the thermostat. If they do it's easy to replace.
The housing around my fuel pressure regulator was leaking a few months ago. Went to Ford and they wanted to sell me the whole housing with gasket and regulator spring. Got the guy to look it up and he was able to order just the gasket for less then $10. Just had to wait a few days.