Check the back of the Game case (Top Right Corner) and see what compatible controllers it takes. If you just see the Zapper (Gun) then yes, but I highly doubt they'd force that on you.
The gun adaptors / zapper are not really functional, just 'cosmetic' pieces of plastic that do not directly effect the game. But they do hold the remote / nunchuck and give a more 'realistic' feel to shooting games.
You can get them quite cheap - like here in the UK you can getr them in the 'Poundshops' (ie for £1)