More:  I think of "computer" as short for "internally stored program computer".  What early internally stored program computer had it operation directed/controlled/... by a control panel?  (Not fair to count the control panels in card reader/punches, printers) 

 The Columbia Computing History, which seems your source, is not consistent on removable control panels.  On the Control Panel page it says 1928.  On the Tabulator page it says Type 3-S 192x had removable control panels, and it says the Type 4 was introduced in 1928.  It would seem that either the 1928 date is wrong or the tabulator type is wrong.  Possible to ask the Columbia person? 

 "Proper wiring of a control panel required a knowledge of the electromechanical design and timing of each machine type." Definitely not!  The control panel presents an abstract machine and you have to know that abstract machine and its timing. How that abstract machine is implemented doesn't matter. In that respect, it's no different that driving a car, or writing a computer program. I wired interesting 407 panels for the IBM Service Bureau and for the US Army Personnel Research Office without ever knowing the electromechanical design of the 407.  I knew there were relays, cams, and a lot of other stuff, but I had no idea about the design - only what what was presented to me on the control panel.   

 "holes or hubs"  No sure what you mean, that hubs is an alternate word for holes?  that panels have hubs or they have holes?  Some control panels have holes, some don't.  As I recall, when I changed "holes" to "hubs" (because "holes" was wrong for many panels) I looked at the IBM manuals and they consistently used "hub". 

 thanks,