Well it seems they recently started shipping them out, so it may take a while. If this is your first time in Kanton Zug it may take even more. I am pretty sure that last year (after my first year in canton zug) I received the forms sometime in June and was given a deadline in September. So it maybe depends on the case. All in all I find the cantonal authorities here not only efficient but also reasonable, so I wouldn't worry whether it arrives late or not.