Joe - On a long bobbin machine you do have to take it apart.
The plate to cover the feed dogs screws down into the bed of the machine, and they are designed for round bobbin machines. The screw goes down under the bed right into the path of the arm of the shuttle carriage on a vibrating shuttle, so you can't turn the machine.
So you are left with two options, either set the stitch length to zero, leaving the teeth static but still there to rub on the underside of the material, or remove the dogs altogether. I prefer to get them out of the way completely.
Whether you can use the feed dog cover with a transverse shuttle, I don't know, I haven't tried yet.