Okay, I revisited the group buy at SBO.com and the vendor we purchased through (aircooled.net), and I found out some things.
Firstly and just as
samcat said, there are two different Kamei spoilers. (Perhaps, I should say
at least two different Kamei spoilers.) One is listed as being for "Super Beetles" and the other is listed for "1968-73 standard Beetles."
Secondly, those who had 1974 and later bumpers (North American market) had to make modifications to make them fit. It was surmised that since the rest of the world never got the larger bumpers, it was assumed by Kamei that Super Beetle bumpers would be a direct bolt-on for all Supers.
That did not deter the buyers of the later bumpers, however. I have attached a
link to page 13 of that group buy where the Kamei was installed by two different people. It is very well explained complete with pics.
I realize
kleinporsche has a standard and wants a measurement. On the first part, I will assume the mods made by the Super owners with the larger bumpers would coincide with what is necessary for standard owners.
I looked up the bumpers a MidAmerica and CIP, and both list the same bumpers for the same years regardless if the car in question is a Super or a standard (e.g. the 1968-73 standard and 1971-73 Super had the same part numbers for front bumpers as did 1974-77 standards and 1974-79 Supers). Therefore, I presume the differences between Kameis for standard Beetles and Kameis for Super Beetles has something more to do with other aspects than the bumpers. And if that presumption is correct, one of the differences may be its size.
I did not see any measurement actually posted. I will fetch my Kamei out of storage as soon as I can if someone else hasn't posted the dimensions kp needs.