1979 Chevy Malibu what additional parts do i need to replac

Hi

I need to replace my Evaporator Core on my 1979 Malibu as it is full with mud, and i don't what to clean it as I am afraid that it will shattered as this is old unit.
now i was told that in new vehicle when you open the closed A/C system it is also recommended to replace a few more parts when you open the system to air.
so my question in my car what parts do i need to replace if i open the A/C system.
the reason i am asking is that i need to order the parts myself from the USA and I am from Israel as the local distributor of UMI can't order the parts for me so i want to make one order that will include all the parts i need for that replacement as if i will forget a part i will be in a big problem as it will take more then a month until i will get it and in this time i will be with no A/C in my car and in this time of the year you can't live here with no A/C in you car.

also i have seen in this site that i am ordering the parts from that there is a kit name A/C Evaporator Core Repair Kit so do i need this also
update me ASAP as i want to make my order fast.

Yours
Tamir