Update 2024.10 (do I need both files?)

Yes, the last two editions of the CN North America map updates (2023.20 and 2024.10) have been delivered as two files ... US in one file, Canada&Mexico in a second file.

The reason is that the size of the full NA map has exceeded the FAT32 file size limit of 4 GB. If you want the full NA map installed on your device, you need to keep both files. If you don't need one of the regions, I suppose you could delete the unneeded file. The larger of the two files is the US map. The smaller file is Canada&Mexico.