Did you already review this report?
http://www.camaros.org/emissions.shtmlThe pump is dated 217th day of (I assume) 1969. The "usage code" per the above link, should be A or C, not U.
Looking at the 1967 AIM under UPC K19 Sheet A5, the correct pump would be 5696104 for a 327 2-barrel. However, I'm not sure if that is also the number you'd see cast on the main body, or a part number for a full pump assembly. But since the AIM shows the plug and muffler as separate items, I tend to think the body casting should match the AIM part number listed. I have a few pumps and will check tonight to see if the casting # is the same as the part # in the AIM. I looked at the GM Parts wiki and didn't get any results at all for your 5696122.
There's a chance that back in the day the original pump locked up and someone went to a salvage yard and pulled your current pump off a 1968 or 1969 GM car. These Saginaw pumps may have also been used on other makes.