Not sure if this info 100% correct but any Simplicity shop can help you with your AC.
Various part numbers and information:
Fuel tank fitting rubber grommet: N1654930 (Simplicity)
NAPA Gold oil filter for hydrostat: 1068 (NAPA)
Hydrostat transmission fluid: Mercon/DexronIII
48" Mower deck 'arbor' belt: N1657044 (Simplicity)
48" Mower deck PTO-to-deck belt: N1722039 (Simplicity)