MacNeish's Definitive Facts lists only the 499 during the '69 model year, Alan Colvin's Chevrolet by the Numbers for '69 does the same. CBTN shows the 2000 distributor for '70 - as you probably have surmised, there could possibly be some late switch to the new 2000 unit due to the late production of the '69 model year. I wonder myself how many 396/350, 396/375, and COPO cars were built between July and the end of '69 production. I believe that topic has been discussed - have to look for it.
If I also remember correctly, 499 production ended before July -
Regards,
Steve