Locally, I am running AEM 220.127.116.11. Our test environments are running 18.104.22.168.
My local has the "Export to Adobe Target" button but the test environments do not.
Am I correct in thinking that if I install the service pack 3 will enable this feature?
I believe that would enable when you create Cloud Service configuration with Adobe Target and select it under page properties on appropriate pages. It should not depend on service pack.
Check in your local if you have an active configuration with Target and the page properties of experience fragment have configuration selected where you see the button enabled.
This feature is available from AEM 6.3 SP2 onwards. If you are not seeing the "Export to Target" button then try restarting AEM or the restarting the "Target Integration" OSGI bundle.