Actually, we know the gap is at least 170k. I posted better estimates earlier in the thread:
PS4 - 395k or higher
XB1 - 235k or lower
Gap: At least 170k (So if PS4 is 395, then XB1 is 225 or less; if XB1 is 235, then PS4 is 405 or more)
Combined: 651k or less (because PS4+XB1 is up MoM by a smaller percentage than 3DS)
It seems that somewhere NPD remarked that every platform is down YOY, though I didn't see this comment myself. If that's the case, then:
PS4 - 395k to 403k
XB1 - 0k to 233k
Gap: 170k+ (e.g. the results can't be 395k:233k, etc.)