Absolutely you can, it could possibly be an oversight, however. But per battalion rules in the CORE RULES it states "The organisation section of a battalion lists the titles or keywords for the units it can or must include. If an entry is the title of a unit, any unit with that title can be used (you can ignore sub headers under the title unless they are included in the entry for the unit).
The battalion states an Saurus Oldblood or Saurus Sunblood. The warscroll for a Saurus Oldblood on Carosaur is a "Saurus Oldblood" for a title with a sub header of "On Carnosaur". They used a keyword Scar-Vet for the scar-vet but the keyword was the wrong thing to use, both should have been titles.