As far as I know Motorola Droid 4 (XT894) was released only in USA for Verizon and its MVNO.
XT894 does not have any network lock or simlock everywhere except USA where it is locked to Verizon (or its MVNO, if device comes from them).
As far as I know there is no way to "fully" unlock the GSM - to use it with other carrier in the USA.

Except that there are mentions on XDA forum about some prototypes slightly differing from this Verizon branded model - for example it had unlockable (or unlocked - not sure) bootloader.

I bought my XT894 from local reseller who must have imported it to Poland from US.