Well, Fred, The Oxford English Dictionary offers no such etymology as yours, with its reference to 'jocularly' and a to-ing and fro-ing over the Pond, but what the hey!
QM, to-ing and fro-ing, as you put it, is my gloss on the entry.It seemed reasonable, since the word originated here and, by my youth, was seen as an Americanism and was not current here in our speech. From memory or deduction, I put 'jocularly', since it would seem that applying it to any man would have been jocular, at least initially. But the history, in terms of usage, is the OED's is it not?
Fred, I wasn't disputing the overall 'history' of the word, merely making the point that no one in this or any other country used 'guy' to mean just a bloke, chap, fellow, cove or man until the 1840s and that initially happened in the USA. How likely is it that the person who first did that had ever even heard of Guy Fawkes never mind had him specifically in mind when he did so?
Let's not forget either that guyS - has very recently begun to be used to mean not just men but also women or a mix of both genders. I’m not at all sure the ladies would be over-happy about being described as “persons of grotesque appearance”!