I would consider myself a trading veteran ever since I recieved around 150 pokemon from a friends FireRed.
Since then I've been juggling them around my games like a mouse on crack.
Originally I recieved them on a Sapphire cartridge, I traded them to Emerald to start Sapphire again, and then back to the new Sapphire.
A few of my old Sapphire pokemon would have streamed into the traded pokemon, I checked the info of one and it said 'Met at lvl 5'.
Not even 'Obtained in a trade', I think it's fair to say I have definitely not trained up a lvl 50 Flygon whilst I still haven't breached the borders of the second town. Has anyone else got this or know anything like this?

Yeh, it's the same for all regions, if a traded pokemon was caught or hatched in the same region that you are in then that pokemon's information will show where and at what level it was caught.

The only difference would be the Pokemon ID no. and Experience gained (unless somehow your cartridge gave you the exact same ID as before which would be a chance in waay over 1 billion...)

~Death