Whatever is in the installer's invoice is included and that can include batteries, panel mounts, and with our house it included a new roof. No point in putting a 30-year solar array on a roof that is going to need to be replaced in 10 years time.
Smart move as electrical rates have already tripled in many parts of the country over the past 10 years and with global warming it is going to get much worse and with more demand comes higher prices.
Get it while you can as the Koch brothers whose businesses profit from dirty coal and oil production have already succeeded in getting the tax credit for solar killed in Oklahoma. Now the billions in subsidies for coal and oil and natural gas and nuclear power are not touched as those are "good" subsidies.