Not sure if you are reusing the struts but on the autoride struts if you let the shaft spin while you are loosening or tightening the nut the struts will be ruined.
The long "nut" on top is indeed the connector for the auto ride.
The nut below that... the one that is counter sunk into the top plate, is the one that needs to be removed to disassemble the struts and remove the spring.
I used a pass through socket set and a pair of vise grips on the tip of the shaft
Something like these...