Carter BBD step-up piston question

[Duodec]

I have a Carter 1-1/2" BBD carb (from a '71 383 engine) that sat out for a while and got some rust and gunk inside.  While disassembling it, the step-up piston got separated from the sheet metal top part that suspends the metering rods.  Not sure how, it came out pretty easily and wasn't pried, it just fell apart while removing.  Anyone know if this is a press-together bit, or is the piston staked in place to hold it in that sheet metal bit?

Currently getting everything cleaned up in an ultrasonic cleaner.  Other than this one issue it is in decent shape.

[Duodec]

after getting it as clean as possible, the answer appears to be... both.

The piston is a very tight fit into the sheet metal but both show faint signs that the piston top was staked to hold it on.