3DS hardmod is only another method to write a NAND.bin to your SysNAND, without needing to boot up the system.
If you never had a NAND.bin from that specific 3DS, you're out of luck. Otherwise, you can use a hardmod to unbrick that bricked 3DS.
In that case, there won't be any more risk trying to get the OTP from your system, because you can easily unbrick with the hardmod method.