I did a major parts replacement on mine a few years back, I had problems with mower movement and researched much about this mower, Anyway, yes the 2 springs for the variator assy. are necessary. I've added a few pics to help you see proper placement BTW ( they are in your Owners Instructions ).
Guess you forgot , I told you awhile back we have the same Murray mowers !!!
OH 1 more thing , if you're NOT useing OEM Murray belts, buy a bottle of Excedrin for those headaches !