I confirm this. This works best when the left hand plays the harmonics in the first octave (rather than in thumb position).A trick I learned from the old-timers when tuning pizzicato is to pluck the string above the left hand(between the hand and the nut) while touching the harmonic A- a nice clear note comes out, the same note as below the left hand but clearer and easier to hear- goes great with the tuning fork.
Hein van de Geyn recommends to play harmonics in this way in his book on jazz double bass.
I do it frequently harmonics (not only for tuning), unless it is really inconvenient. As a bonus, it looks like bass wizzardry to the puzzled audience.