Don't most chips generally do all-core OC that matches their stock single-core boost? At minimum. So the boost clocks here would represent a theoretical max all-core OC.
Yea 2700x has single core boost of 4.3ghz I think and even though I got mine running stock. My OC does max out around 4.2ghz all core. So I would suspect around 4.7ghz minimum from the 16 all core OC. Given those numbers are legit.