I believe you are right, in fact Mitch McConnell said to Tony Snow just today, if the votes were needed they WOULD be there.
You know, a lot of this is for the benefit of the press too IMO. Gives them something to report at night, I'm convinced.
My guess is the vote to end cloture will be 51 or 52. I suspect the republicans have 54-55 votes if needed. They may allow 1 or 2 senators to vote against if they already have enough votes.