Any actual proof of Lambda on Aspis?

[Lyceum]

Lets not forget the 6th century Attic black figure that shows the letter A. Using letters on teh shields as emblems clearly was not a Spartan innovation, and whenever used we don't have to asume they were used universally. A few of the same letters in the front rank of the enemy could be used to identify them if there ever was such a problem.
Khairete
Giannis

There are also a number of lead tokens from 4th and 3rd century contexts at Athens with various pieces of kit on the front and letters on the back. The ones with shields all have alphas on the face of the shields. Kroll, "Some Athenian Armor Tokens," Hesparia 46.2 suggested that they were related to the distribution of public equipment. So three authors and two kinds of art seem to support the idea that soldiers from a city sometimes used the first letter of that city's name as a shield blazon, but only one attributes this to the Spartans.

Just flicked through that and one or two articles he cites. Interesting. Those seem to date from the 3rd century, though the author suggests this practice derives from earlier periods with either α or αθε marking state sponsored equipment. Interesting and this might well fit in what we know of classical age Athenian policy of giving armour to war orphans, which they themselves made a big show of. Assuming that armour was state commissioned and not provided by some liturgy (and aren't these behaviours normally the same thing?) But that can't be too widespread and is, at best, analogous.