Still searching for a good pictorial schematic of the "Jupiter-C" skirt, which I believe is the source for your light. It could be the telemetry port, that looks to be in the proper position based on the video.

I've searched through much of the Redstone and ABMA material that is on-line. Beginning to wonder if the skirt and instrumentation package that sits atop the stretched Redstone was a "JPL special" since the Jupiter-C which is actually not derived from a Jupiter missile, but a Redstone adapted for high altitude research had many components unique to that configuration, especially in the instrumentation and skirt that sat atop the rocket. Could this have been work performed at JPL instead of ABMA? I believe that is where the Explorer satellite originated from. But of course the skirt, instrumentation section and spinning "tub" all pre-date Explorer I and are an integral part of the "Jupiter-C" design used to test nose cone re-entry by a few years. However, it could be that JPL still played an important role in the development of these special adaptions. Need to dig further into "Project Orbiter" and JPL documentation stream.

So ironic that there is plenty of pictorial documentation out there on the rocket itself AND even the upper stages (2, 3 and 4). But the instrumentation & steering nozzle skirt, not so much, and I don't think it's a classification issue either as most of this material was declassified as early as 1964!

Dave