What type are you referring to? For the 737 it isn't a gust margin or a stall margin, it is a margin to stick shaker and "adequate" is not 40º+, it is 15º + 15º overshoot. "Full" is defined as 25º + 15º overshoot.
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For the 737, "full" manoeuvre capability is only "guaranteed" for takeoff flap and V2+15 or the flap setting and the associated flap manoeuvring speed. That means that between V2+15 (flap 5) and say 190kts (flap 1) it may be assumed to be less than "full" manoeuvring capability. The word "guaranteed" is only used in association with the "flap manoeuvre speed" and not the EFIS speed tape "minimum manoeuvre speed" amber band. The amber band is calculated differently. However, Boeing does say that the amber band and the flap manoeuvring speeds are independent means of assuring "full" manoeuvring capability. Which is a slight contradiction to what is written elsewhere. You decide what is safe. For me I will continue follow the Boeing recommended practice for an immediate turn which is unambiguous.
In the 744 the amber band, which is normally well below the flap maneuvering speed, gives a 1.3G stall margin, which is defined as
• 1.3g maneuver capability to stick shaker with flaps down
• 1.3g maneuver capability to stick shaker or VREF+80, whichever is less,
with flaps up below 20,200 FT
• 1.3g maneuver capability to low speed buffet (or an alternative approved
maneuver capability as preset by maintenance) above 20,200 FT.
Note: 1.3g maneuver capability occurs at 40 degrees of bank in level flight.
Since stick shaker is also above stall speed (flying with intermittent stick shaker is the recommended technique for terrain avoidance), it is exceedingly clear that there is adequate stall margin for flap retraction according to the normal schedule, while turning and accelerating after takeoff.