If we suspend the typographical discussion for a moment, the argument in favour of 'les unit' is that it is at least part of a phrase found elsewhere on seals, whereas 'le2 unit' would be nonsense. If you Google L'amitié les unit and sceau you'll find them all over the place.
Seems a valid argument, this one. The garbled S makes much more sense than the garbled 2, of course, as Dantius comments (although he has not repeated accurately the strokes but has just drawn an S over them, he could have just as well drawn a 2
).
So, to sum up, the inscription on this oject, whatever it is, and it is most probably a seal of a kind, is
Les unit, which is a part of
L'amitié les unit or, might be
L'amour les unit, the first part being omitted for some reason, or rather symbolized by the two hearts pierced with an arrow.