Try Ag Belting Outlet, 620-845-0814

I replaced the belts on a JD 567 baler.  Learned they cut belts to size from large rolls of stock.   Your part number may guide them but it may require measurements.

I asked them price/cut a short strip 92"x18" for the output flap on a 735 moco,  They politely took my call but never called back with pricing.  I dropped the issue because it was so small.  Win some/Loose some