Determination if an MP5 is designed to fire full auto or bursts by markings on gun

[Etraveller]

Hello.
Is there any way to determine if the MP5 A3 (retractable buttstock), 9mm calibre submachine gun, fires in the full auto mode, or in bursts by looking at markings on the gun or how the trigger mechanism is assembled?

Also, if the gun fires sporadically, i.e. 1 round, 4 rounds, 3 rounds etc,with each seperate pull of the trigger (i.e. gun fires when trigger is depressed and held , and the trigger needs to be released and depressed again to fire again). And the primer is unindented, or round doesn't appear to be jammed.

What are the possible problems causing this? (Dirty chamber/trigger mechanism, worn sear?)
Also the release lever has some lateral (side to side play on it....)
Etraveller

the gun has the general selector with S,E,F.

 

[silicon wolverine]

According to my HK refernce book the SEF trigger group is full auto. The problem youre having is possibly a weak dissconnector spring or a worn out disconnector.

SW

 

[MisterPX]

A SEF pack is originally safe, semi, full. However, with those issues stated, you need to check out your trigger pack, and if you don't feel qualified to repair it, send it out.