Have we seen an alternate timeline already? by The_Noose

For some time now I have been reading over the many wonderful theories posted on this site. After reading one particular theory (Sorry I dont recall who posted it) that mentioned Cesar finding notes in Ben's office in the old Hydra Station. This post having to do with the diagram of varying time lines coinciding with various "events". I then started going through the screencaps page looking for the sheet. What I found along with the diagram, is the basis for my theory.

Have we already seen evidence of an alternate timeline? In Ben's office there is also the discussed LIFE magazine talking about nuclear testing. The date on the magazine is April 19, 1954 indicating that the test shown was done sometime prior to that date. Seeing how our Losties visited 1954, at the location of a proposed test sight, and the convenient placement of this magazine, is it safe to assume that the noted test in the article is the test f! rom OUR island? If so, what has changed to prevent the test from happening? Has our LOST crew's venture into 1954 affected the outcome of that test and thereby creating an alternate timeline from that point on? In an alternate timeline, did the test occur and interact with the EM field on the island causing an even earlier "Incident"?
This might just be me reading into the scene a little too much, but the placement of the magazine seemed to be of enough importance to specifically shown in that scene.

This magazine article (combined with the Army Photo of the Island from the Lamp Post Station) may give weight to there being prior iterations of alternate timelines that we are only seeing hints of, that may at some point in the final season help develop the "Big Picture".
Thanks for hearing me out. If I am completely off base, I look forward to reading your comments.