CC2531 - unused USB

Hi everyone,
I have a design in which I use CC2530 but as it is harder to buy and is generally more expensive I want to replace it with CC2531. And here is my problem - in cc2530 pins 1 to 4 are connected to GND while in CC2531 they are used by USB. My question is: can I mount CC2531 instead CC2530 without changing the board when I'm not using USB?
Thank You in advance,
Peter