Question about the pml.

Can you follow what the score says on a piece about instrumentation or do you need to follow what the piece is listed under in the pml.

Example

A piece is under the flute trios on the pml - but score says option to have 2 flutes and 1 clarinet - can you perform it with 2 flutes and 1 clarinet or does it have to be played as a flute trio.