Section 1 as an experimental is definitely possible—that has happened many times before!
The overlap of RC in section 3 on both tests is unfortunately not proof that 3 was your real RC. It could be that 3 was the real RC on one test form, and then that 1 was the real RC on your test (see
http://www.powerscore.com/lsat/help/experimental.cfm for more info).
Also, the appearance of double-question stimuli is no certain indicator that a section is experimental. I talked about that on a recent blog post (see
http://blog.powerscore.com/lsat/bid/323 ... ng-Stimuli ), and the gist is that recent experimental sections have featured these questions. And things that appear in experimentals eventually appear on real sections. That said, it doesn't mean that section was real (it just doesn't prove it was experimental)