Thank you!
But I am not sure about the versions. My 11302 has a set of EPROMs with -06 revision index and it is the 2.7 version (see attachment) . On TekWiki, the files for the 11302 has a revision index of -03, thus older, I think.
Maybe that the 3.1 version is the one of the 11302A? Many things let me think so, for example I saw a photo of a 1302 with a label "Updated to 11302A".