If you want to make it AVAILABLE for upgrade, as opposed to make upgrade automatically, you can create one of the requirements for the upgrade instead of research the level of the upgrade.
Like, NumberKills = 100, create 1 Blacksmith at YourRegion facing default building degrees.
Then, if you don't want the Blacksmith sitting around, you could create it in some random corner of the map away from everything else, and give it the locust ability.