As far as I know all were rebuilt from 4 board to 5 board sides and the Dumping mechanisms removed by the end of the 1920's. Although some may have had the dumpng mechanisms removed earlier. There is a george Beam photo of 1464 in Alamosa dated 1923 which shows a newly painted 4 board car with out any dumping mechanism ("George Beam and the Denver and Rio Grande Volume 2" page 18).
I have seen a photo, from the 1950's, of a 5 board, 9 stake car which seems to show the footprint of dump rod bracket impressed into the lower side boad. I have a list of AFEs for the rebuilds from John Templeton. However I will be unable to to access it and the rest of my material in these cars until next week.