Printing 2 sided coin, can I design the 2 halves separately and put them together before printing?

So far I’ve been developing a few version of this coin/medallion, and every time I have to remake the design, or copy the design of the full coin, then extrude the design for the second half and then subtract that part to add it etc.

I was wondering if I can simply make the two halves individually, then place the two disc one over the other, and send to print. A friend told me this wouldn’t work, as they would appear as separate objects.

So essentially if the coin is supposed to be 0.4 thick, I’d make two halves of 0.2 and then out the halves together before sending the file to the slicer.

Yes, you can do that. Just place them back-to-back (easiest with the Align tool) and then run a Union operation on them.