The FCTM states that the boeing 737 is classed as category C for straight in approaches.
For an 800 at flap 30 according to the graphs in the FCTM, 1.23 Vs at max landing weight would be right on the 140/141 kts boundary for Cat c or D, so presumably for flap 40 would be below 140kts (no graphs for flap 40 are given in the manual)
For the classics there is no problem, on a 300 1.23Vs at MLM is approx 125 kts for flap 30.
Hope that helps.