Sounds like a bad case of "I'm the man" syndrome to me! I don't believe that a shop would tint your entire windshield, but if they did it would be easy to tell. Around the border where your dot pattern is, the tint would have to be cut back from that - or it would have bubbles there. If not you've probably got a factory tint - I don't think they can make a ticket stick for something from the factory! Who is your windshield made by (should be identification in one of the lower corners).