Yup, my rather large workplace (in the Fortune 100) switched from XP to Win 7 just about a year ago. We have IE8 but they will also let us use an ESR version of Firefox. Other business units than mine get to use Chrome, too.
I work for an org that just upgraded from XP to Win7, however we went straight to ie11 as the default browser during the upgrade. However, optional use Firefox and Chrome is permitted for both XP and Win7.
Just a guess, but for example, i know for a fact that the german telecom is doing this XP->Win7 migration in the coming months...