You're absolutely right, Vergilius; these are pretty clearly prutot, even though many of them are underweight. The most you can say is that the most underweight may have circulated as lepta. As far as I know I'm speculating, but it isn't impossible for evidence to turn up. A number of small
hoards of 139 prutot have been found; 128 prutot equals the half-shekel
Temple tax, and other eleven presumably represent the
money changer's commission, as it would have to be exchanged for a 'proper' silver coin. It would be interesting to know whether any of these coins figure in them. I think
hoard evidence could answer a lot of questions about
Hasmonean coinage, but so far I haven't seen any studies relating to it.