Ummm, they didn't? Much less the Citation Mustang is the 2012 plane, and is a completely different type of plane. That is kind of like comparing a Honda Civic coupe to a SUV! One is good for single driver, the other is good for the whole family.
Ya, the Citation Mustang is definitely a 2012 plane! Though the 2010 plane I think is still listed as for sale......so maybe they meant both?