First time that I know that AOA "units" are not degrees.
So I've looked into the T-45's NATOPS Manual.
And yes, you seem to be right. It say only "units", not degrees.
Page I-2-90:
2.21.2 AOA Controls and Indicators.
2.21.2.1 AOA Indicator. The AOA indicator
functions throughout the entire flight regime to
display AOA information, see Figure 2-38. The
indicator registers units of AOA to the relative
airstream, from 0 to 30 units. An OFF flag is
visible if electrical power is lost. The indicator is
set with the optimum unit setting at the 3 o'clock
position. Both cockpit AOA indicators independently
receive their input from the AOA probe.