If you didnt set a default password you can try 1234, 0000, and 9999 - those are the other defaults other than the last 4 digits of your phone.
If you can access the filesystem with BitPim you can either do a Hex Dump of.. or simply save and open nvm_0002 - you'll see the 4 digit code there.
nvm_0000 gives you your 6 digit SPC lock code

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