I dont know about that. The fact that The Torah uses “Shana” to describe the length of time he lived (x969) is certainly an indication that it means year as it does throughout Tanach.
I grant that it is possible that length of a year was different at that point. (though there is no indication that this is so). So if it makes you feel better. nu nu. But to say there is no indication that “shana” means what it always means is a stretch