The first and only stage is at the fat pin contact with the intermediate lever. As the trigger is pulled, the fat pin rises up against the intermediate lever and when moved far enough, disengages the sear. All of the trigger parts are stamped out and none of it is machined and most internal parts are designed with clearance purposes in mind. Depending on what gun clone and who the manufacturer is, the intermediate levers differs. It can be Spanish, Mexican, Brazilian, Turkish or Chinese. I've even seen years ago, a two part lamination intermediate lever and sear but I don't remember what it was in. Many of them have little differences built into them but use the same basic design and same over all functioning measurements.
However, my point is that the fat pin does not determine the second stage....cuz there ain't no second stage.