Seems IV./JG 54 was not disbanded, rather becoming IV./JG 26 later in February 45.
But yes, it was a four Staffeln Gruppe... this site helps yet again.
http://www.ww2.dk/
http://www.ww2.dk/air/jagd/jg54.htm
(so IV./JG 54 this perhaps was only drained of suitable trainees)