At around the 2:26 mark there is guitar that plays an E harmonic.......is this the effect you are meaning? (Open harmonic on the top E (1st string) at the 12th fret.
There are ,many things that do seem to become audible even after hearing these songs for years.
One that I can hear quite easily now is the few different set guitar tones that play the Brighton Rock intro and verse parts. Before I assumed it was 1 or 2 same sounding guitars but now after hearing the original master tracks it is very obvious that the few different set guitars all add nicely together....... Almost like 1 plays neck and bridge (with bridge out of phase), 1 plays the usual bridge and middle in, then a much more wooly one...possibly neck only? but perhaps different amp mic positions???
I've become aware of lots of 'lost in the mix' stuff since doing transcriptions for many years. Using a filter from say (Transcribe!) or Adobe Audition really lets you isolate lots of things.