Confused about iPad Serial Numbers and Generation - Help Needed!

Hello Apple community, I recently purchased an old Apple iPad (5th generation - 2017) from a marketplace, and I noticed something peculiar about its serial numbers. On the back cover, the serial number reads "DMPTL3GRHP9X." However, upon checking the serial number inside the iPad (in the Settings), it displays a different one: "DMPJJ6K8F186." Additionally, when I used the Apple website to verify the serial number, it showed that the iPad belongs to the "iPad 4e génération - 2012." This discrepancy has left me quite confused about the actual generation of my iPad. My concern is whether the iPad has been tampered with or if there is any possibility that components from a 4th generation iPad were replaced with 5th generation components, even though it shows the 5th generation in the "About" section in Settings. Has anyone else experienced a similar issue with their iPads? Can someone from the community or an expert shed some light on this matter? I want to make sure I have an authentic 5th generation iPad, and any guidance or insight would be greatly appreciated. Thank you in advance for your help!