I can't tell from that spotlit photo; @lovedogs may be correct about the tone.
And it is so far away in the photo that we can not say anything about clarity, window, etc.
I do not know that lab to know if it a reputable "heat-only" call or just "heated-at-least and who knows what else?"
Appealing price for a nice face-up size in a 4.5-ct seemingly-saturated blue sapphire but there are too many variables with missing data here.
NGI is a well recognised lab in Singapore. The thing that worries me isn't the lab report, it's that the vendor had to shine a flashlight at the stone to photograph the colour. Count me in the "suspicious it's too dark" camp.