Hey Steveboot
Welcome to the site.
The 2nd Gen bandits are jetted pretty lean from the factory, especially at sea level. You CAN install an aftermarket can without a jet kit, but you get much better performance with the jet kit as well.
Two quick things you can check:
1. Pull the seat and check the air cleaner cover. Most jet kit companies recommend drilling extra holes in the lid and removing the snorkle. If there are extra holes, you can be pretty sure it has a jet kit.
2. Look under the carbs (you may need a small mirror). The factory pilot air screws are covered with an aluminium plug. If you can see the brass air screws, than someone has removed the plugs to adjust the screws, another giveaway that someone has modified the jetting.
These bike make a LOT more power with a jet kit, airbox mod and aftermarket slip-on. If you want to go back to stock, there are likely a few guys on the board with a stock mid-pipe and muffer to sell, but your performance will suffer.