[Rixter]

I can't believe you're considering not doing it.... 1st thing I do on any 928 without records
while the potential for valve damage is quite small with the early cars it does happen, so do old belts breaking, I've even seen 1 split right down the center into 2, and skip 3 teeth in the process
the potential damage to other parts, ie cams as noted above, alone should be enough to convince you to do it
the job is not that difficult, especially on an early car.... get the parts and invite the local 928 crowd over for a tb/wp party