maybe earlier than the one shown above as it lacks the FCC and power information, or simply had no info on the back for aesthetic reasons

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I'd imagine that the reason for that system lacking the sticker on the back with FCC and power information would be that that stuff wouldn't be finalised until fairly late in development, therefore there's really not much point in designing a sticker to put on earlier systems - they'd just have to redo it later on down the track when they get the FCC approval data and stuff, not to mention that prototypes aren't FCC approved, and since not many prototypes would have left the US, having the power information isn't really all that neccessary.