Far Cry 3: Blood Dragon is about as far away from Far Cary: Primal as you could get, at least in one franchise. One a neon soaked romp through 80s nostalgia, the other a bloody and brutal trudge through an aggressive pre-historic landscape.
Yet, there is a pretty cool Blood Dragon easter egg in Primal, which shows the skeletal remains of the titular Dragon. This video by OniZombies (vg247) shows is in all of its glory and where you can hope to find it if you want to track it down.
Take a look: