That's a model 19 Briggs. It has the rectangle points box cover and magnamatic ignition coil under the flywheel. The coil part number is 290880 if you need to replace it and they are available. The Briggs 19D has a 3 leg armature mounted above the flywheel and the flywheel has magnets. The coil for the 19D is part number 296834 and became unavailable recently. Great little tractor you have there. There is a timing procedure that you must follow if you remove the aluminum coil mount from the block.