ok, all except one
no need to be sorry Les, learn something new every day and it don't muddy things, but clears them up
in fact I see now the assembly manual [called 55-59, but actually from the beginnings of the series in 55] list an RPO 249, which is 'Dual tail and stop lamp' - never noticed that before [but nothing to do with signals], dealer installed items, like the 2nd taillight on a pu [#987458], were accessories, and that light was standard by 1960
no doubt had to do with the evolution of state lighting laws, which around that time were changing all over - most likely in 54/5 there were still many states that didn't require 2 brake lights on trucks, by 59 I believe all jurisdictions required 2 rear lights on all vehicles
I've seen 5-6 panels and burbs without the signals [including a
friends 56 here], and never seen one that didn't have the standard tail lights - note also that the door brake light was dropped at the end of 56, so RPO249 became regular production .... so it appears there is the possibility of finding the occassional 55 or 56 without the outer lights, but I'd bet they're few and far between .... more valuable?
Bill
