1984 Oldsmobile Cutlass engine replacement

I have been considering having the engine replaced in my vehicle and i recently took it to the shop to have some work done and i was told that i needed a new water pump and a timinig belt change. my question is should i have these done prior to having the engine installed or will these have to be replaced as part of having the engine installed. i am just unclear as to what is included when an engine is replaced is it just the required belts, hoses, etc.?? Thanks