Cavalier Steed -- Which base version?

[Smog]

So looking at cavalier steeds, I see it operates as Druid's animal companion, which makes me think I need to use the horse statistics listed under druid, but the light horse in the bestiary has slightly different stats, as does the light horse listed on the srd.

So I'm still assuming I should use the druid animal companion stats, but it seems odd to be that they're different than a base horse from the bestiary.

[Cheapy]

All animal companions have different stats than their bestiary versions. Use the animal companion stats!

[Starglim]

The only thing an animal companion horse takes from the Bestiary is the Docile trait, making its hooves secondary attacks until it becomes combat trained at 4th level, but the cavalier's mount begins play with combat training anyway.