Well now, that is a very good question. My sons truck had 170k on it when we installed the 235's and the old ones look great. I need to have them checked before I put them into the back-up stock. But the way it ran and the way they look, I'm thinking there OK. What plays a big role in their life span is how well they were taken care of.
Maybe Piers would know for sure. But why would you want stock injectors anyway? No disrespect intended.
-dave-