All Catholic women are required to wear hat/head covering during service, so naturally it would be same to meet Pope. It is requirement of the religion....not on street or regularly, but in any Mass or Church, The Vatican.
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Actually I believe this requirement was abolished by VC-II, but I could be wrong. In any case, nowadays very few women wear a head covering at Novus Ordo (new order) Masses. Those who worship at Latin Tridentine (Latin) Masses however, usually do wear a head covering, but those Masses are far and few between.
You are correct, change in Canon Law 1983, it was omitted.
However many women do not choose to make that change, as Bible stated women should cover their head.....most interpretations took it to be for the Angels. I am not Catholic, but have attended Mass with friends.
https://churchpop.com/2014/12/08/10-reasons-women-wearing-veils-church/