Richard was born on Thursday, December 30th, at 7:07 AM. The only person who guessed the correct date was gwiii (he also guessed 11:21 AM, so he wasn't that far off). A few people were off by a day (debbikins and little_boots guessed the 29th, and forkintheroad guessed the 31st. Everyone else was too early or too late. (New Year's Day was the most popular, with four guesses).
He weighed 9 pounds and 11½ ounces. Nobody guessed correctly, but there was a three-way tie for the closest guess: jennae, little_boots, and thetaet all guessed 9 pounds and 8 eight ounces. Tied for second place were allah_sulu and samphire69, who both guessed 10 pounds. gwiii gets an honorable mention for "Slightly less then 250lbs. Hopefully." ladycrim gets the "that would have been nice" consolation prize for being furthest off, with a guess of 6 pounds, 3 ounces.
He was 21 inches long. Not many people tried to guess his size; but 2mermaids, forkintheroad, and samphire69 all guessed correctly. bouncepogo, call_me_emanon, and cthulugrrl were each off by an inch, in various directions.
EDIT/ADDENDUM: The average of all of the weights guessed was 8 pounds, 12.2632 ounces; people tended to be too low rather than too high. Oddly enough, the average of all of the dates guessed was December 30th.