...the details of extra-nonce parameter for the relevant transaction disprove that totally.
Honestly, it doesn't really prove or disprove anything. The nonce theory suggests which blocks were mined by a single computer, but Satoshi easily could have been mining on more than one computer.
Yeah, the second computer might explain that nonce discrepancy, no matter how little it is, providing that second one was mining sporadically, assumption which contravenes (in my view) objectives of sustainable confirmation on the miserable network as it was in 2009. SN can hardly be compared to that man who don't understand the importance of every node when the net is weak. However, the second computer might make sense in your mind.