Answer
It depends on the policy you hold with allstate. but remember that if anything happens to the suv you rent, your insurance will end up going up.
when you rent from a car rental compny they offer you insurance, for like $9 a day you can cover the vehicle bumper to bumper with no deductible, and you dont have to contact your insurance if nothing happens. thats the best bet.
i used to work for 2 car rental companys, and it really is easier just to get the insurance through the comapny like that.