What is the difference between a precision timer and LinCMOS timer?
Precision timer is the original bipolar device, LinCMOS timer is a newer unipolar (CMOS) version.

In general, bipolar ICs are more rugged with higher VCC limits and strong push-pull outputs.

On the other hand, CMOS has much lower power consumtion and lower input currents.

For the 555 timer, the default choice is usually bipolar, unless you need low voltage (2 alkaline or 1 lithium coin cell) or low power consumption. Both types will give the same result.