Spread offenses vary in execution, schemes, etc. Some are more run-heavy, some are more pass-heavy, etc. Regardless, though, none of the college spread offenses will have near the extensive playbook that pro-style offenses do.
While Brian Kelly's spread offense more closely resembles a pro-style offense than others (think of it as a simplified K-gun offense, the one that Marv Levy used during the Buffalo Bills Super Bowl appearance runs with Jim Kelly at the helm), it still lacks a sizable chunk of the fundamentals that a pro-style offense uses. That being said, at least QB's who come from his offense have a better understanding of timing passes, as well as downfield passing than most other spread QB's.
I have little doubt that Deshone Kizer will be able to learn those fundamentals in a short time. At least he didn't get suck with a run first mentality, like spread option QB's do.
If anything, what Jackson said could be said of any of the offensive players on a spread offense. Some offensive linemen who were in spread option offenses might not have had any real exposure to zone blocking schemes that a lot of pro offenses use. Many a wide receiver came out of a spread offense not understanding the full extent of route running, and needed time to learn.