Are you sure. Realying omn the telesnaps, it's difficult to be sure, but as far as can be seen from this
http://4.bp.blogspot.com/_NoKHO38EA...6QxNgEEhk/s1600/Sonic+Screwdriver+%282%29.jpg
it certainly looks to be Hartnell's prop, and there's records of the list of props kept for the Doctor's pockets from the time which confirm the pentorch was still there at the time of Fury, while Michael E Briant recalls that they used a prop they already had to hand for the sonic to cut short a very cold filming day (though the evidence is ambiguous: there's also some records of a special prop being scripted for use; one explanation is that the daft script included the sonic, it was changed to a conventional screwdriver, but on location it was changed back and the studio scripts kept consistent with the material already shot).
In this shot from War Games, it's very definitely a pentorch, and looks pretty simialr to the Fury one from what we can see of it.
https://upload.wikimedia.org/wikipe...rewdriver.jpg/220px-1st_sonic_screwdriver.jpg