They may be able to add some plays - but I have a hard time seeing them installing an entirely new offense.
Frankly - I would be surprised if they could execute all that well with an entirely new offense after only 2 weeks.
What they'll likely be looking for are tendencies - more likely to run or pass under certain circumstances, etc. Remember - this dude, as an OC, had his offense performing in the 120's. There were 120 teams with better offenses - for 3 consecutive years. I don't imagine we're going to see an offensive explosion.