Yes, that is the general idea as it eliminates the air gap between the thermistor and the block which acts as an insulator, with the void filled with cement it lets the thermistor react quicker to temperature changes coming from the block. Just be very careful to not let the thermistor wires become shorted to the block or themselves, this is where the kapton tape or any tape comes in handy to hold things right where you want them while the cement dries. Just remember it makes it more complicated to replace the thermistor when it fails, on my first one I actually mounted it without cement for the initial test of about two weeks... after that I figured it if it was defective it would have quit in the first week so I went ahead and cemented it in 
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