Almost certainly. We see it again a few scenes later lighting up room with only Harry, Ron, Hermione, Crookshanks and Scabbers (Pettigrew) present.
He, Ron and Hermione went to the library next day, and returned to the empty common room laden with books which might help prepare a defence for Buckbeak. The three of them sat in front of the roaring fire, slowly turning the pages of dusty volumes about famous cases of marauding beasts, speaking occasionally when they ran across something relevant.
Crookshanks’s fur suddenly stood on end. A shrill, tinny whistling was filling the room. The Pocket Sneakoscope had become dislodged from Uncle Vernon’s old socks and was whirling and gleaming on the floor.
‘I forgot about that!’ Harry said, bending down and picking up the Sneakoscope. ‘I never wear those socks if I can help it …’
The Sneakoscope whirled and whistled in his palm. Crookshanks was hissing and spitting at it.
‘You’d better take that cat out of here, Hermione,’ said Ron furiously; he was sitting on Harry’s bed nursing his toe. ‘Can’t you shut that thing up?’ he added to Harry, as Hermione strode out of the room, Crookshanks’s yellow eyes still fixed maliciously on Ron.
Ron, of course assumes that it's down to Crookshanks rather than Pettigrew.