Probably the only item you require for the air-filter assembly is a new air-filter cartridge 1AE1445100 or 1AE1445100P; but if the air-filter assembly has physical damage, or just looks miserable and neglected, then maybe more replacement parts maybe required, both for sound mechanical reasons (no unfiltered air entering the carbs) or perhaps just cosmetic reasons - or a mixture of both?
Other related components you may wish to view: