RE: To early to rattle?
A month before the rut you can try spar rattling(light/low toned tickling/not aggressive)to entice bucks in. Though this usually results in immature bucks. So to anwser your question it depends when the rut takes place in your area?
I usually don't rattle till week(or so)before the rut, this when the bachelor groups arelong split off and the bucks are starting to chase does. My best success on mature deer comes this time throughearly post rut. Like anything it doesn't work everytime.
Good luck