So, he averaged 5.7 BLK/G for a whopping 7 games (after they went back and gave him credit for 7 more BLKs). Most of the BLKs were against guys a foot shorter and one or two may have been goaltending (hard to tell from angle in the video).
Regardless, between 1985 and 2006-07, five players (and seven more came close) averaged more BLKs/G for a full season (at least 28 games) at the NCAA Division I level. I'm not sure how a "prospect" is being defined, here, but I consider every of of those 5 seasons more impressive than Yama's accomplishment. In all cases, the sample size was 4 - 5x as much, in most cases, against better competition.
And that doesn't even include Manute Bol, who in his one season of college ball (at Division II Bridgeport) averaged over 7 blocks a game for 31 games.
Unfortunately, the NCAA did not keep track of BLKs back when Wilt, Russell, Kareem, Artis Gilmore, Walton, Mark Eaton, etc. played.