For the newer "Slim" PS Vita (Model PCH-2000), the location changed slightly.
The PS Vita homebrew community is massive. If you are looking to install Custom Firmware (CFW) via HENkaku or Enso, the model and serial number range can help identify which motherboard revision you have (e.g., the "Fat" 1000 vs. the "Slim" 2000, or the rare PlayStation TV). Some serial ranges are tied to specific factory firmware versions. check ps vita serial number
If your PS Vita is bricked or the screen is dead, you might still retrieve the serial number indirectly using a memory card and a PC adapter (SD2Vita or Card Reader). However, this is not a direct method. The serial number is burned into the syscon (system controller) of the motherboard, not the memory card. For the newer "Slim" PS Vita (Model PCH-2000),
Important clarification: You cannot get the console serial number from the memory card. However, if you previously used Content Manager Assistant (CMA) on a PC, the backup folders are often named using the console's ID. Look for folders created by your Vita on your PC hard drive—sometimes the root folder name contains a truncated version of the console's serial hash. the "Slim" 2000, or the rare PlayStation TV)