Wild horses = Mustangs?

[samoht04]

Yeah, I created my Mustang when I created my Sims toon - and I thought I had read somewhere that the wild horses you can adopt are Mustangs, but it's also likely I just dreamt that.

It could be that one of the Challenges for the Riding Skill (Sims Journal) has Mustang in the title and the challenge is to adopt 3 Wild Horses, that gave me the impression that they were Mustangs but reading here I guess you can't be too sure.