Bitmain stated in an earlier post that they only had an S2 farm and 1 S3 for testing. They could be lying who knows. The recent 24% could have been from other mining hardware being turned on and tested. Also if people are getting S3's and the parts smell brand new, then that's another indication that haven't mined with the S3's. It would take multiple weeks of running the S3's for the difficulty to raise 24%. I would think a couple weeks worth of use would be noticed by customers receiving their miners.
I do not think so. Their S2 farm is already sold empty.
Yesterday I got my last S2. It was apparently used, cleaned, and the main was very scratched. He was used with Rack Mounts, because of the mounting points were bent out. The housing cover fixing poits was different from all my previous miners. I've bought them before 15 units at different times and had not seen this disain before.
I think that they are now S3 farm.