The water level was 150 feed (50m) lower than today before melting of ice.
And it was successful, they did find them under water.
How Paleo-Americans Emerged From The Ice Age | On Point with Tom Ashbrook: "We go under Lake Huron to see how America’s paleo-Indian mastodon hunters lived and moved at the end of the Ice Age. Plus: new studies suggest that the Antarctic shelf is collapsing for good.
9,000-Year-Old Caribou Hunting Structure Found Submerged in Lake Huron | Popular Archaeology - exploring the past
"Discovery under 121 feet of water in Lake Huron sheds light on prehistoric caribou hunts | MLive.com
Irreversible melting of Antarctic Ice Shelf has started, to result with eventual sea level rise of 10 ft. It will take some time, but will change geography.
What Does U.S. Look Like With 10 Feet of Sea Level Rise? | Climate Central
Cities that will end up mostly submerged (or protected by sea walls):
New Jersey | Surging Seas: Sea level rise analysis by Climate Central