Back in the day when this info first came out, it was reported that some valve and seat damage could occur in as little as 75,000 miles without the lead additive.

75,000 miles is a long time in most occasionally driven cars, and then the "damage could occur in as little as" comes into play. Most read that as the damage could possibly start in 75,000 miles, not that it would, or was guaranteed to.

Funny thing is, before the mid 70s, it was not uncommon for some cars to show signs of needing valve jobs by 75,000 miles, and few motors lived past 100,000 miles.
If I had a motor apart it might be something to consider, but I'm not pulling a running motor down just for this purpose. I'll take my chances. I've driven a lot of high miles Mopars. Defective valves was of little concern, the motors often outlasted the cars. Gene