At least one G5 has a G550 nose, inc EVS
There is at least one G5, with a G550 nose.
Caused some problems when nose attacked by tow truck once, wrong nose delivered twice. Major practical difference is number of retaining clamps.
Apart from that, Captain on G550 have 5 stripes, so easy to spot in crew room, as well as they will tell you anyway.
glf
waiting for my 6th stripe