recent 3GS + 06.15.00 => bricked. Baseband chip replacement?

Hello all,

I bought a 3GS stuck in recovery mode and found out that it has no baseband (no IMEI, no Wifi, no Bluetooth, ...).
It's serial is xx150xxxx so my guess is that the previous owner installed the iPad baseband in a jailbreak attempt, so it's bricked :-(

From what I understood, the recent 3GS/8GB have a baseband chip from a different brand, not compatible with the iPad baseband.

My questions are:
1- because I assume we'll never get any baseband downgrade program, can I simply remove the baseband chip and replace it by an oldest one, are they pin-to-pin compatible?

2- if I replace the baseband chip with a brand new one bought on the internet, will iTunes be able to program it if it's totally blank? Does the new chip need to have at least a boot program/version identification or something?

Thanks in advance!

Nobody knows?