Another thing is that Satoshi included a hidden message referencing The Times newspaper on the genesis block's coinbase timestamp parameter (The Times 03/Jan/2009 Chancellor on brink of second bailout for banks) and never mentioned it.
That message was put in there to give prove no mining was done before that date. So it was there for a purpose.
Since Satoshi was very strict about privay it wouldn't make sense he intentionally created a way to distinguish blocks mined by himself.
That's exactly what led us to explore Satoshi's blocks. If he wanted his blocks to remain private, he wouldn't change the nonces this way. What's the reason to mark them? He would have known which blocks he mined, so there was no reason to do that. One reason could be: he wanted us to see these blocks.