The G4 was the last Kirby to use the gasket around the fan opening that fits into the groove. Starting with G5 they went to the unigasket.
The gasket part number is 122068A Nozzle Seal Ring (Sanitronic VII thru G4)
The belt lifter has been replaced by the G5 and later style along with the sticker on the front.
The Headlight cap is riding on this bar that has a screw at each end that goes into the top of the slide bracket assembly just behind the fan case. Once you unscrew that bracket and lift up on the headlight cover then you can get to the 3 screws that hold a cover over the bracket and plastic wedge in the shell itself.
