The SHIELD logo maybe, but the photos could have been taken years earlier then just picked out to use when the bunker was setup.
Generally speaking such photos of the boss are kept more or less up-to date. A few years at most. So it was most likely abandoned in the late 40's, early 50's at the outside.
It'd be different if they had left the organization, but we know Peggy at least was active until the 80's and Howard probably until his death in '91. At least I assume so since it was implied his death was arranged by Hydra after he'd cottoned onto them somehow.
I don't think there'll be a huge jump to season 2 anyway, maybe 1948 at most, unless they want to imply the 1947 Roswell event was an SSR experiment with repulsor technology and start there.
Nevada isn't all that far off from LA for a setup to the season.
I tend to agree that they probably won't jump ahead all that far. A year at the outside maybe?
Ohh, not Roswell. I'm so sick of the Roswell myth. It gave us a killer Futurama episode and a funny DS9 episode, but it's been done entirely to death by this point so pleasepleasepleeeeeze let it die already.
Funny you should mention that: a while ago I was freeze framing all those documents that flashed up during Zola's big exposition dump looking for easter eggs and (after a google search) one of them as it turns out appears to have been lifted from some supposed memo regarding MJ-12 that's been re-printed in several Roswell conspiracy theory books.
The curious thing is that the content memo itself is fairly innocuous and the in version that flashes on screen in the movie, the mention of MJ-12 is redacted. Apparently someone in the art department is a conspiracy theory buff and/or has a sense of humour.

Also of possible relevance is the Avengers prelude comic that has Coulson's team using a SHIELD base in Roswell as the staging ground for their operations in 'Thor'.
There is at least one small mercy: we know the Kree corpse wasn't from the Roswell incident as that thing was in Reinhardt's possession some two years prior.
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