Purchasing Warped Roof 1997 Bigfoot 2500 9’6”?

Those hatches are known to fail due to fatigue and weathering but are readily available and cheaper than a Heki hatch. I would be more concerned with the window seals than the pool of water next to the hatch unless you see signs of water inside the roof. Look for water damage on the inside lower portion of the window framing to see if the windows are beginning to leak.