From what I have dealt with, I would say pre 2000 N/A would be safe.
Engine that is in my car now (98 WRX), I bought not realising that it had snapped a cam sprocket in half. Belt was on but was way out. New sprocket and belt and has never missed a beat. Same deal with an early (94ish) GC8 motor that I worked on.
Seen plenty of 99 + WRX engines bend valves though. Seems to be hit and miss.



(Pun intended)