The fcc requirement is that VERIZON WIRELESS doesn't do anything to block device usage. It does not apply to manufacturers who can block to their hearts content. My old droid razr maxx cannot be used on usa networks, neither can my moto luge, which was launched in August 2014. It can be hacked to work on att and tmobile though, cannot do it out of the box.
With that said, most recent phones are factory sim unlocked. But it depends on the specific model.
As said before, the note 4 is factory sim unlocked.
Even unlocked, USA networks can be blocked(as with my moto droid razr maxx and moto luge) , and on top of that, the usa apns can be locked, meaning no data (as with the note 2 at release, though this restriction was removed after an update). The s3 I believe was factory locked, but later unlocked via update.
Sent from my Verizon Samsung Galaxy Note 4