The kids were hanging on the shower curtain and broke the pot metal mounts. I'm not sure what exact brand, but this is the same shower rod they sell at Bed Bath and Beyond or Home Depot. So, I measured up and made a copy of it. I'll be installing tonight, but I think the second attempt is a success, because the hole pattern matches the wall, and it fits the shower curtain end.
The two side holes need to be tapped with 1/4-20 tap to accept the bolts - this is how they hold in place. Uses all the original mounting hardware. I printed with 2.5mm wall thickness, 30% infill and .3mm layer height. It took 6.5 hours but the part is solid as a rock!