I dont think anyone in FPSC will confirm it at this stage. They will simply ask you to read the rules- thats it. And the rule does not mention Urdu or English anywhere.

This will then solely depend on the examiner that how he/she puts the instruction at the top of the paper.

Since the word Urdu/English have been completely expunged in the rules, this must contain a reason - most logical of which is that they want the respective language to be used while answering. So they might put that very instruction at the top giving a surprise to all the exam takers.

It is also possible that they instruct otherwise- It depends on the individual now. Is he/she ready to take the uncalculated risk?

These are just my understandings.