If the rebuild was 23kk ago how come the cambelt's let go already, please tell me someone didn't rebuilt the shortblock and slap the same belt back on...
Pistons are probably fine unless you smacked a valve so hard the head of it came off and bounced around the chamber for a while, in which case the block is probably toast too. We bought a motor that had seized the cambelt (when the chassis rail hit the cam pulley, lol) and the head itself and pistons were ok, just needed valves.
10/14 hours labour feels pretty light for engine out and rebuild heads? But then the parts cost shouldn't be massive either.