I’m not sure if there’s an actual name for them, but those triangular sections aft of the wing roots are an inflatable seal (made of rubberised canvas) which closes the opening left when the wings are swept forward.
I don’t know if it may be specific to an individual aircraft, but Medium Grey uppers does seem a bit suspect. Medium Grey does form part of the TPS colour scheme but not the overall upper surfaces. Check here for the standard colour schemes: http://www.anft.net/f-14/f14-detail-colours.htm
I would suggest going with something along the lines of 36081 since that is a gray used on Navy aircraft and it “looks about right” compared to that image.
I want to say that area of the aircraft is called the wing glove, but I am not certain on that term for that part.
Typically, the wing glove is the fixed structure which extends outboard of the fuselage sideline.
The inflatable seal is prominently visible on the F-14 because of the high mounting of the wing. When the wing sweeps back, it “rests” (for want of a better description) on the upper surface of the fuselage. On other VG aircraft, such as the F-111, B-1 and Tornado, the wing enters the fuselage when swept back. These aircraft also incorporate inflatable seals but they are less visible as they are enclosed within the fuselage.