Now HardOCP throws some cold water on this by pointing out that not only Lenovo has removed this mention since then, but also that "GTX 1160" was on that product page in June of 2018.
The site believes this was little more than a placeholder rather than a fresh leak:
We reported that Lenovo was (incorrectly) calling Nvidia's next gen graphics cards the "11 series" around that same time, and the "1180" they mentioned turned out to be part of the RTX 2000 series. While that doesn't definitively debunk the mobile GTX 1160 rumor, and says nothing about the alleged desktop variants, I think the "GTX 1160" listed on Lenovo's site is probably an old placeholder instead of a new leak.