Reading over the GS3 sprint official forums I came across this post from "SprintCare" the sprint representative to the forum.
So therefore I purpose that 4.4.3 is indeed confirmed for sprint galaxy s3.
Link to original post
SprintCare May 16, 2014 3:34 PM (in response to strangebrew52)
strangebrew52, Google is aware of the issues associated with the KitKat update. They are working on 4.4.3 which is supposed to help with this. I understand how frustrating this can be and we appreciate your patience while we wait for Google to release an update to correct these issues. Lorrie Sprint Social Care
So therefore I purpose that 4.4.3 is indeed confirmed for sprint galaxy s3.
Link to original post