overflow of particlecounter for rigid body

Hello,
I work with a large number of rigid bodies. Every time the number of rigid bodies oversteps approx. 65.000 I get the error:
No rigid bodies defined.
I guess it is because the nbody variable is defined as 16 bit integer. How complicate will it be if I define the nbody variabe as unsigned long at the fix_rigid.h file?
Will it work still fine?
Thanke you for your help.

Best regards
RoberG