There seems to be no simple answer, though prior to 1942 the Typhoon had a surface with the trade name 'Wondergrip', a sort of rubberised material, cemented to the wing to form walkways. From 1942 onward " A satisfactory painted on walkway has been developed at Langley and tested in service. This is now applied to all production Typhoons".
This would imply that Hurricanes too would not have acquired a painted on walkway until 1942 at the earliest. Pictures of the unrestored Finnish Hurricane show some kind of strip attached in this area. The problem is that there are plenty of photographs showing this 'strip' worn back to bare metal from the Battle of France and Britain period.
Cheers
Steve