Look through the font list carefully for a scond listing for Gill Sans. It might be showing as two families.
Thanks for your reply!
I've checked all fonts now and it seems that Indesign categorizes some of my T1 fonts as Opentype. So there really is multiple families and only light cuts are showing as a Postscript font.
I downloaded a trial version of Suitcase, and activating fonts with manager, they all seems to be Postscript fonts.