Yah, I don't know if the original bolts only grab about a 1/4" of thread and it broke when they worked on it or if it was broken previously. Maybe both bolts were made longer after the first boss broke? I still think they should have mentioned something and/or used a couple washers or something for a spacer. Apparently not all 3204's use a separate bracket that the oil cooler bolts to. I think it's an oil galley from the injection pump to the oil cooler. I got the disassembly pages and it shows the oil cooler bolting right on the block. At least now I have an explanation why it broke.
I put a bolt in the broken piece and wrapped some masking tape around it. Then I put some epoxy on to build it up. I let it set till it got stiff and then turned the bolt so it wouldn't get glued in. I got the bolt out easily this morning and amazingly the masking tape came off even easier from the epoxy. It was still sticky! The epoxy isn't fully cured but it says to wait 24 hours. Seems to hold on the cast iron OK though. I'll drill it out and file it to the right height.