MaxPreps does show Conley as outperforming the national average in all offensive categories, including SB. Not surprising for a team that has been very successful.
Agree that SB is among the least reliable of HS stats for the reasons stated by stats. Really all the moving pieces in that vicinity are problematic. For example, you might see a pitcher for one team in a HS game get dinged for 5-10 WP that a catcher at the next level, or even the catcher on the other team, would have handled.