Yes, I believe they are all 3/8 - 24. That is also the thread for the brake light switch. If you still aren't sure, you can always see if a 3/8 - 24 (or as JB says, 3/8 fine thread - same thing) screws into it.
I suspect that the M/C is using two different threads to distinguish between the front and rear circuits. 3/8 - 24 is the thread usually associated with 3/16" tubing.