Hello! Your operator appears to be a match for our 39-253LB. Look it over and see what you think. Note that we also sell the 39-253RB for the opposite handed side.
As for removal, after you take out the screws it should just slide out. The only thing I can suggest beyond that is to ensure that both arms are disconnected from the sash, but that should be all you have to do.
That depends on the age of the window. Some years ago, these were made so that the original white cover was permanently affixed to the operator and was not meant to come off in any way. It was only recently that Truth changed the design so that the cover was something that could be removed.
On the newer operators, the cover just snaps on, so it should be removable by hand. If you find that to be difficult then odds are yours is the older type whose cover can't be removed.
