The leakdown numbers are pretty high but you mught want to put some miles on it and retesting before proceeding. If it has been sitting for a while, driving it will tend to improve the readings. Also, make sure the engine comes up to temp before starting the test. Do you know what brand of leak down tester was used? There is quite a variance in readings.

Generally I consider 10 to 12% leak to be normal for a used engine in good condition, with anything past 20% a sign of needing a rebuild. On race engines, I cut those numbers in half.