In earlier models that 4 dimpled retainer screwed in, and was removed using a 4 pronged removal tool.
Not sure I recall what happens in a Commando, but don't try pushing it out just yet !
You often see them munged up on earlier models, where previous owners used a punch or cold chisel to bash them in or out ! They are surprisingly expensive to buy or find in good condition for earlier models too.
I'd guess that Commando ones have different threads...