There are certainly later depictions such as this, now lost plaque from Pergamon

- Battle of Magnesia?
- conze_1913-bd_1-text_2-pg_251.png (187.93 KiB) Viewed 9206 times
Don't get me wrong, I have much respect for Hatzoupoulos, not least because he ' shows all his workings' and thus saves any one who takes a different view a great deal of work hunting down the raw data

For my money he extrapolates the ordered Antigonid Kingdom back onto the Argaead a tad too much, but such things are frequently just down to interpretation due to the state of the evidence. Miltiades has probably (no, certainly) seen the original but, like you the photo is not clear for a definite pronouncement.
The ones i am discounting are earlier vase paintings, which are hoplite shields nonetheless, will try to find an example.
Was anything said about the coin finds?
When you think about, it free-choice is the only possible option.