Both the main and nose landing gear wheel wells are the same color as the exterior of the aircraft. The following information was taken directly from the MH-53E Detail Specification.
3.2.6 FINISH
Finish and protective coatings shall be in accordance with MIL-F-7179. Exterior surfaces shall be aerodynamically smooth. In addition, permanent and removable hydraulic lines and fittings located on the rotor head, in wheel wells, and in those areas exposed whenever the tail pylon is folded shall be painted in accordance with paragraph 5.9.1(a) and (b) or MIL-F-7179, up to approximately 1 inch from each fitting. Color shall be black polyurethane No. 37038. Interior permanent or removable hydraulic lines shall not be painted. The organic finish for exterior surfaces shall be MIL-P-85582 Type II primer, and MIL-C-85285 paint, with the exterior color painted flat engine gray (FED-STD-595) color No. 36081 with markings applied in color No. 35237. The main transmission cavity between stations 322 and 362 shall be light gull gray, No. 36440, MIL-C-85285. Dynamic components that receive exterior paint finishes, such as rotor heads, drive shafts, transmission components, etc. shall be painted as follows: (1) those surfaces that are externally visible shall be painted black polyurethane color No. 37038; and (2) those surfaces that are not visible externally shall be painted light gull gray polyurethane color No. 36440. Main and tail rotor blades shall be painted all over with lusterless black color No. 37038 except for two locator stripes for the blade handler on the main rotor blade. Wash primer, MIL-C-8514, is required as an undercoating for epoxy primer on corrosion resistant steel, nickel, or chromium plated surfaces.
3.2.6.1 EXTERIOR COLOR
Exterior color shall be in accordance with FED-STD-595, color No. 36081 (Gray).
3.2.6.2 INTERIOR COLOR
Interior color shall be in accordance with MIL-C-8779 except that camouflage dull black paint to match FED-STD-595, color No. 37038, may be used in the cockpit, and that pilot and copilot seat cushion color shall be black.
3.2.6.3 INSIGNIA AND MARKING
Insignia and marking shall be in accordance with MIL-I-18464, except that exterior insignia and marking shall be polyurethane FED-STD-595, color No. 35237, and in general accordance with Naval Air Depot (NADEP) Drawing No. D38875, dated November 17, 1977.
Hope that helps.
Stephen