Is it necessary to replace the SMD fuses in RAMPS 1.5 or greater, for use with 24 volts?
Without knowing the exact part numbers used for F1 and F2 it is impossible to say whether the fuses need to be replaced or not. However, based on the manufacturer provided schematic and BOM we can make a pretty good guess.

Looking at the PDF you linked, it states that F1 is rated for 16V. Looking at the BOM spreadsheet it also says F1 is 16V and 30A.

Based on the fact that the only two reference documents available say 16V, I would strongly recommend replacing this component for 24V operation.