vishnu wrote:I looked fairly closely but I don't see anything that looks like a date stamp.
Chalk that up to my poor photography skills!
In the first photo, just below the blue-on-white sticker with the Sun logo that says "Assembled in USA" is a smaller sticker that says 1294 which might be a date code. Whether that's month 12 or week 12 of 94, I don't know.
There's also what looks like a date code in the copper itself in the second photo. Between the tiny writing and the glare of the lights it is unreadable in the photo I posted. But in the top left, near the big black dot, there are some symbols in the copper alongside the numbers 05-94 (rotated 180 degrees).
It wouldn't surprise me if 05-94 is the date code for when the board was etched and 12-94 refers to final assembly. Of course, they may not be date codes at all! But 1994 certainly seems plausible.
Thanks guardian452 and robespierre for the insights on the squares of copper. I'd wondered about their purpose, too.