Chances are good that you will need new rotors as well.
May as well be prepared. You can always use them the next time...
No special tools required for the 124.
Metric hex key to remove rotor set screws, but this is not exactly 'special'.
Easier than average as brake jobs go.
The front is particularly easy on your early 1-piston model.
The rear can be something of a pain due to the inherent complexities of the parking brake, but still easier to deal with than many other cars with the same config.
Probably worth searching old posts for 'best practice' techniques, and reading up on braking systems in general if you have never done brake work before. While brake work is relatively easy, it is not a place to be taking shortcuts or risks.
1986 300E 5-Speed 240k mi.