Datsun vs Datsun?

Well, looks like I've got a bit of investigating to do.

STRANGE thing I have come across just now : "Similar to its predecessor from 1969, the GT-R was available as a coupe (KPGC110) and a 4-door sedan (PGC110)."

Four door GT-R's for the C110 ??????

source: http://www.skyline-nissan.com/skyline_history.htm