There is a little rotational room where the air vent/fill valve end-cap connects to the manifold body but it may leak if too far unscrewed. If it does leak, you'll need to leave the end cap tight and swap the air vent and fill valve. Sealant is used to connect the vent and fill valve to the end cap, so it will take some muscle (and maybe some carefully applied flame) to unscrew them.
There is a little rotational room where the air vent/fill valve end-cap connects to the manifold body but it may leak if too far unscrewed. If it does leak, you'll need to leave the end cap tight and swap the air vent and fill valve. Sealant is used to connect the vent and fill valve to the end cap, so it will take some muscle (and maybe some carefully applied flame) to unscrew them.