The difference between 'self' adjusting and 'non' adjusting brakes is an actuating cable and adjusting lever that engages the adjustment star wheel.
Pull the rubber plug(s) on inside lower area of backing plate.
Shine a good strong pin point flashlight in and see if there is a lever (bar) sitting on top of star wheel.
The star wheel can not be moved when manually adjusting brakes without lifting that lever up off star wheel.
And if you have NO documentation of trailer having self adjusting brakes probably doesn't have them........typically those are an upgrade/option vs standard equipment.
The EZ-Lube and Torsion Axles are standard on your trailer