Very Nice job on the Rounds, Totally empathize with the "customer" situation, I have done custom work for a similar crowd "war gamers". With re-enactment being toy soldiers, but on a different scale. *)
The main issue I found was that people do not comprehend or choose to ignore, that it does take a lot of time and skill to replicate items such as this. Especially something as bespoke as a 60mm mortar round replica, as such they tend to want the moon on a stick and at half price.
That is my main reason for explaining the processes involved and it's time requisite per unit when quoting for work of a similar nature.
( casting in metals and resins usually)
I think they may find Customs would have a dicky fit when they arrive on that slow boat from china.
Someone brought a live P.I.A.T round into work a couple of years back, which they found whilst walking the dog, that was an interesting day.