It's possible if it can maintain 200,000 per week sales until Black Friday as you hypothesized. I can't say this would happen for sure because of the Wii's price cut.
But if 200,000 per week sales till BF happens, it proves there are 50% increase in the sales per week basis. Given FFXIII release in Japan this Christmas, if PS3 can achieve 50% increase during preholiday, attaining this during the actual holiday season should be no problem.
In conclusion, next couple weeks I believe will tell your hypothesis is correct or not.