Looks like you would be ok to me, but if you want to give yourself peace of mind just replace the track nuts (with the built in washer which is usually around 4mm) with a standard nut of the same depth and a slim washer.

Track nuts have no thread under the built in washer area so (effectively) removing the built in washer (by replacing it with a standard nut) engages no less threads on a standard axle - (in the illustration below the two threaded areas of both nuts are the same).

P.S. the axles are the same length on these two pictures, the lower one looks longer but that's an optical illusion.

Black = axle
Pale blue = fork end
Orange = track nut with built in washer





Black = axle
Pale blue = fork end
Pale green = standard nut
Darker green = washer