Yeah, for some reason Rochester pumped out a TON of those carbs for service replacement requirements. Do a search on ebay for 7029207 and you'll find lots of over the counter, early to late 70's dates. I have one on a 396 in my garage that was assembled the 83rd day of 1972. My theory is that they may have used this carb for multiple applications in a service environment, but of course, that's just a theory.
For the 1969 Corvette, a total of 12,846 L46 (350/350) cars were sold (no breakdown of auto -vs- manual), but there sure seems to be a ton of service carbs for this engine!