Perhaps. However, Musk said that less than 250 miles EPA range is too little and the Model 3 SR+ battery in the Model Y would be less than 250 miles EPA. So, they would need a somewhat bigger battery for a Model Y SR+ to get to 250 miles EPA range and that adds complexity that I don't think they will attempt. I suppose a software locked LR battery is a possibility but I'm guessing they won't do that. We shall see.