Lift or Leveling kit?

I have a '99 Superduty that has either a 2 1/2" lift or a leveling kit on it. It was installed by the dealer before I bought it. I've asked numerous people about it and get different answers. I've measured the block under the rear springs and it measures 2 1/2" taller than the stock blocks I've measured on other F250's. The springs up front are obviously taller but I'm not sure by how much. How can I tell if it's a lift or just the leveler?