rotary encoder with mp3 lilypad

Hey everyone! So I am working on this project which is using rotary encoder soldered onto mp3 lilypad board. My problem is I bought the RG one and I am not sure if it will still work.. It seems it does not really fit on the board since there's space for 5 pins (which RGB rotary encoder has) whereas the RG one has only 4.

HELP thank you