Go-kart leagues and races frequently have a set of rules and regulations, particularly FIA-sanctioned races.
Mostly, you will be capable of reading these race regulations on the organizers official site. At times, the rules and regulations are also available upon registration, so make certain that you read through them well.
Mostly no particular reference is made to the usage of a tire prep formula. As you do not desire to risk the possibility of being disqualified, it is always best to check with the sanctioning body or the race organizer directly.