When I went to pickup my M3 from Birmingham it wasn’t at the pickup centre, it had been taken to the service centre for a software update. FSD was enabled when it turned up later.
If that was recently its probably because there was a legal issue with EAP and FSD that prevented Tesla deliving the car with the older software. They'd have taken the car for the update. I wouldn;t read too much into it.
I don't actually think Tesla are that sophisticated when it comes to matching to be prioritising some orders over others. Based on past evidence it's more likely to be just poor administration. What is worth remembering is that there isn't just a Model 3 list and a Model Y list.
There is a queue for each of:
M3 RWD, White paint, Black interior, standard wheels
M3 RWD, White paint, Black interior, upgraded wheels
M3 RWD, White paint, White interior, standard wheels
M3 RWD, White paint, White interior, upgraded wheels
etc etc
An order that seems to move more quickly than yours could easily be down to it being slightly different. There is also a suggestion that things like the upgraded wheels or expensive paint might come sooner, but whether thats a deliberate ploy where Tesla just skew the production towards them as they're more profitable or just a quirk of what people order is a guess. I recall when the Model 3 came out, they stopped taking orders for the white interior for a while, the thoguht was to push new orders towards the black interior to balance the order book a little.