Does the Cabrio (1998) ELX have a pollen filter? If so what is it's part number?

Does it have aircon? If it does, there will probably be a pollen filter. If not, then very unlikely.

If it has one, this is probably it. Don't order one until you know you need it. If not fitted, the housing will be glued up(by Fiat), so cannot retrofit one.
https://www.shop4parts.co.uk/?name=...iat_Punto_(1993_to_1999)_1.2_8v_Pollen_Filter

No aircon, so there we are! One less thing to worry about! Think of all that power through no aircon!