defacto,
You would have to look at your particular variant to see what they used as the reference for Vref CAT...usually I see it as the median weight, not MLW, with flaps 30. This sets the aircraft reference CAT,
Here is what Boeing supplies as the Ref CAT for the aircraft...you would have to back through the calcs to see what weight/flaps, to get that approach speed.
(I think a quick way is the check your QRH, I have one for the 737-700 right here...the Ref CAT from the Boeing table below is 129kts...looking at the QRH, that is a 55T flaps 30 match...
http://www.boeing.com/commercial/air...oachspeeds.pdf