I took apart my 2600 (4-port) in preparation to install the electronicsentimentalities.com S-Video board.
Compared to all the other 2600's I've seen, this one is odd because there is no silkscreen at all... all the component locations were meticulously hand-labeled with a fine marker.
The board is ©1980, rev 8. There is no serial number on the bottom of the case - just a red sticker "Atari Super Service".
I'm guessing this means nothing exciting (like a prototype), except this was a rebuild/repair (and Atari was cheap enough to recycle a batch of PCBs that came out without the silkscreen).
Unrelated - I'm excited to finish wiring in this video daughterboard (this is why some TIA pins are unseated).
I hooked the 2600 up to my LCD TV using the original RF, and it was unwatchable. On an older tube TV, it was a little better (but still full of static).
The photos I've seen for completed installs look awesome! :)