Doug Smith has an interesting page detailing challenges in grading ancient coins, using these COL-NEMs as examples.
Augustus & Agrippa
struck c. 10 BCE - CE 10, Nemausus
AE dupondius
Obv: IMP/DIVI F, back-to-back heads of Agrippa, in combined rostral crown & laurel wreath, and Augustus, laureate
Rev: COL - NEM; palm tree, top bent top right with a wreath above; crocodile chained to palm tree
Ref: RIC 158; AMC 425; Cohen 10; RPC 524
From the collection of a Man of the Cloth, now giving up the pursuit; acquired in the 1990s