Yep thats an electric start engine, missing the starter motor, you can see the ring gear on the flywheel. I have the motor here for one. The sump was also different as the fill bung is normally in the way.
The colt was offered with electric start, although I have never seen one, so it is very possible that its original.
Best thing for the filter is a new one, they are easily available at any briggs dealer.
I would definitely be interested in the engine, i would also take the whole thing depending on what you want to do
