I’m personally not the greatest fan of sand park as, but it’s to much of a risk removing as it who knows what’s hiding underneath...
Thanks! I fell asleep last night before answering your question. Sorry! You'll see those divots called various things but on this board they are typically called centration dimples or more accurately, "lathe dimples". They are the result of a flan-making process in which the not-yet-struck flans are turned on a lathe to make the surfaces more even. There have been many discussions about them but here's a post by @Roman Collector in which he coins the term "lathe dimples" and he provides a often-shown link about the flan making process.
No worries, and Many Thanks! I like it when explanations of things like this, that I would never have imagined, make this level of improbably immediate, intuitive sense! Thanks for the link to Roman Collector's post, too.
Constantius Gallus - AE3 Obv:– DN CONSTANTIVS IVN NOB C, Bare, bust draped and cuirassed right; A behind bust Rev:– FEL TEMP REPARATIO, Soldier spearing fallen horseman, who is wearing a Phrygian cap, reaching backwards Minted in Siscia (// BSIS), Reference:– It would appear to be unlisted unless I am missing something. It measures 19.20 mm and weighs 2.44 gms