Swapping a deck shell is not hard... just tedious and very detailed.

Take lots of pictures of the old deck from EVERY angle and then take more. A parts diagram in your hand is a big help also. Pay attention to belt guide and tensioner location.

Go area by area and swap one thing then the next.

Check spindles and idler pulleys for smooth operation. If any don't feel really smooth then replace the bearings or the assembly.

Many decks use tapered thread (self tapping without nuts) bolts for the spindles and you might snap off a bolt and might have to drill one out so have the correct tools and spares. Don't just use whatever bolt you find on the bench or in a jar as a replacement.

Make sure you torque the blade bolts to the proper spec.

Putting new spindles in the budget is a good idea as typically you will break at least 1 bolt off in each rendering them useless. Most likely you will be replacing the idler cam and possibly brake arms too. 169583 is the part number for the complete deck and they have been coming with the new 4 bolt spindles which is a plus. They can be had for under $400 , assembled & shipped to your door.