Yeah, you're close. You seem to be suggesting that any measurement causes the interference pattern to disappear implying that we can't actually observe the interference pattern. I'm not sure if that's what you truly meant, but that isn't the case. Disclaimer: I'm not an expert - I could be mistaken.

The particle is actually being measured in both experiments, but it's measured twice in the second experiment. That's because both experiments measure the particle's position at the screen while the second one also measures if the particle passes through one of the slits. It's the measurement at the slit that disrupts the interference pattern; however, both patterns are physically observable. Placing a detector at the slit destroys the interference pattern, and removing the detector from the slit reintroduces the interference pattern.