Yes, eFuse will shut down a phone with an unapproved bootloader — but it won’t brick the phone, it just needs “approved software” to be dropped back on there.
In other words, the bootloader is locked, but it won’t kill the device if tampered with. Running custom ROMs is still pretty much impossible, though. In short, the situation isn’t as bad as it looked earlier in the week, but the Droid X is still far less hackable as the Droid.
Which is still a bummer.