I've had a look at the insulators and carbs this morning.
The head inlets are all in line, the insulators are all in line and the carbs are all in line. So the insulators are the same length and not angled.
However measuring the head, the centres between the inlets are different. Between 1 and 2 the centres are approx. 65mm, the same for 3 and 4. The centres between 2 and 3 are approx. 70mm, this is because the cam chain runs between 3 and 4. The centres on the carbs are all the same, approx 67mm.
So the insulators have to be in the right place and the right way up because they have a dogleg. Easy to see on number 2 and 3 when you look for it.
Installed with 1, 2, 3 and 4 at the top (left to right) the carbs line up with the insulators.
Installed incorrectly would definitely make it more difficult to mount the carbs. I guess also would greatly increase the risk of air leakage and poor running.
Typo, the cam chain runs between 2 and 3.