Hi.
"Existing Type1 fonts will appear as “Missing fonts” in the document."
"Many fonts published by Adobe Type in the past (such as Adobe Originals) are available from the Adobe Fonts service for free with your Creative Cloud subscription."
So, as I understand: you will be able to open .ai files that contain Postscript files but you will get a “Missing fonts” message, however, you can replace it. Some Postscript fonts could be available on Adobe Fonts and you can use the "auto-install" Illustrator function.
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