I believe that's the number required, but they have to gather extra signatures in order to make sure they've got enough valid ones. In efforts past, the California Teacher's Association has even had people purposely sign phoney names so that their signatures would be tossed. Dirty tricks abound in these things.
The correct number is 879,136 valid signatures. That is 12% (from Article 2, Section 14(b) of the California Constitution) of the 7,326,133 people who voted for Governor this past November.
Therefore it is reasonable to aim for 1.2 million raw signatures, which would meet the target even if the validity rate was only 73%. Getting that many raw sigs also makes it likely that they could be validated through a sampling procedure, which would speed up the recall election by several weeks.