Prefix will be a good time and you will be favorably impressed.
Getting to go to the Plant on an individual basis has always been virtually impossible , as the concern about commercial intelligence leaks is inevitable ( as they have happened way too much in the past). The Plant gets daily requests, and it is impossible to screen all the folks wanting to stop in, plus they would need to hire full time personnel just to do the tours. With different projects going on , often secret, to find times when one could go through, or when workers can be advised of visitors , becomes a logistics issue.
The Plant has been very good over the years letting in groups from various Viper Clubs and Dealer Groups, but they are all scheduled and the Plant will often have areas shuttered off prior to the tours.