However it looks like this just changed: https://www.nhtsa.gov/sites/nhtsa.gov/files/2022-03/Final-Ru...
“For vehicles designed to be solely operated by an ADS, manually operated driving controls are logically unnecessary.29 To account for this, the NPRM proposed a regulatory scheme in which the affected standards would not assume that a vehicle will always have a driver’s seat, a steering wheel and accompanying steering column, or just one front outboard passenger seating position.”
They are apparently allowing level 4 Taxi to be considered full ADS even if they have additional “Stowed controls” options.