No. It wouldn’t be expected.
To start with, that “P1” is just an in-house identifier and unless you know the manufacturer, an approximate date when it was made, and probably the package style, “P1” on its own is more or less meaningless to the average consumer like you and I. The days of useful part numbers on the package are gone. The parts simply got too small.
You can find dozens of very different and very non interchangeable parts all labeled P1.
2nd, why would you expect a P-channel FET in a MCU controlled “low side switch” like this application?
An N-channel FET makes good sense. P-channel makes no sense and would be… difficult… to drive as a low side switch.
If I was looking for a replacement for those output MOSFETS I would be searching N-channel parts.
Something with the same package style (looks like maybe SOT23), the correct pinout, logic level gate, Vds > 40V, Id ~ 2A, Rds On = “lower is better”.
It’s a very non-demanding application and you can probably find dozens of parts that will work great at Digikey or Mouser for under $1ea in 10qty or greater.
LOL, no the MOSFETs are not protection for the optocouplers.
The MOSFETS are used on the output of the MCU as a low side switch in an open drain configuration. (Gate to the MCU, Source to ground, Drain is output). They are used to drive stuff connected to the OUTPUT of the controller.
The optocouplers are used on the INPUT of the controller to isolate and protect the inputs of the MCU. They have nothing at all to do with the MOSFETS on the output.
MOSFETS? They’ve been around since the 60’s and popular in tons of applications since the 80’s.
My first encounter with them was mid 70’s. But yeah, I’m an old guy too so sometimes it does seem like just a couple of decades…