Easy Street
The fairing there is an outer flap element inner flap track fairing. The outer fairing has a landing light incorporated, so it is the inner fairing. The inboard flap in the Yehudi area between the engine strut and the fuselage has a quite different fairing, that was a redesign of the JT8D engine pylon which incorporated the flap track on its sides. On the NG and Max, this was redesigned and the vestigial -100/200 inner flap track was changed to a similar system to the outer flap tracks. Peter Randolph wrote an excellent report on je transport high lift devices which IIRC covers in part the design changes. He also indicates the inherent design problems on the T/E flap tracks which cause so much irritation to owners of B737's by a poor choice of design by the OEM which results in unnecessarily high loads on the track/carriages.