Some people were aware of at least some devices on coins. Cassius Dio,
writing under the
Severan dynasty, describes the
EID MAR denarius. Beyond that, there's two references I know of that might describe instances of
collection, although they are open to be read in different ways.
1) "On the Saturnalia, and at any other time when he [
Augustus] took it into
his head, he would now give gifts of clothing or gold and silver; again coins of every device, including old pieces of the kings and foreign
money; another time nothing but hair cloth, sponges, pokers and tongs, and other such things under misleading names of double meaning." (Suetonius, Life of the Divine
Augustus, 75).
I'm not sure whether this shows that the ancients were collecting coins for anything beyond their value, unless they also collected clothing - but then again, since Suetonius does mention "old pieces" and "foreign
money", there might be something of an attraction towards the
rare and exotic.
2) Pliny the Elder mentions people apparently collected fourrés. Or at least, bought them as an object of study: "it is astonishing that in this art [coinage] alone one studies the defects and a sample of false
denarii is examined, with the adulterated coin bought for manifold the value of the real one"(Pliny, NH. 33.134).
Beyond that, the only similar
collection I have come across in ancient authors is Pliny, NH.37.11, where he speaks of the first
dactyliothecas, or
collections of gemstones/intaglios. Not sure whether we can infer from the existence of such
collections (by
Sulla Scaurus,
Pompeius, Mithridates...) that coins were likewise collected for their motifs, though.