What's the difference between a decade counter and a "Divide by 10 counter"(MOD 10 Counter)?
These days you would generally not build a clock like this with a batch of counter ICs and miscellaneous gates. Any questions regarding count modulus, which type chip where and this flip-flop versus that flip-flop go completely out the window when you use an MCU for this type project. 

Several other things come along with the MCU based type clock too:


You can deploy a low cost I2C chip with battery to provide the RTC function that continues to work when you turn off the main power.
If the clock counting is done in software it is only a small amount of code to implement the clock function easily to support additional time features like seasonal time changes, time zone selection and century support.
It is far easier to support setting the clock using an MCU than it is with the discrete counters. Plus the setting can be inputted by buttons, serial port, from GPS receiver, or even from a WWVB receiver.
Interface to various types of display is much easier with the MCU. If you use seven segment displays it is easier because it is straight forward to reduce wire connections and multiplex the display.


I dare say that you will learn just as much about clocks and electronics using the MCU approach, if not more, over the 30 year old discrete counter approach.