Nope, for Yonex, G5 = thinner slightly longer grip G4 = fatter but shorter grip eg Weight of 3UG5=3UG4
The lengths depend on the model.. NS9K, NS9.9K, NS8K, AT900's and the AT800's have long grips while the others dont..
for ur info... regardless of the grip size is g4 or g5 or even g3... the lengths will be still the same... as long as is the same model...