I can partially answer that. the xt1050 is a device sold by 'regional carriers'. for example, I have an xt1050 but which was sold by alltel. there are other xt1050 models sold by Inland Cellular, Illinois Valley Cellular etc. Basically the xt1050 was the model sold by very small cellular companies. I can't vouch for other models besides the one i have but my alltel xt1050 was able to be unlocked officially via moto website. I was also able to install twrp on it.
But it gets more complex. There are apparently different firmware versions for each different xt1050 model. see this page here
https://motorola-global-portal.custhelp.com/app/answers/prod_answer_detail/a_id/94927/p/30,6720,8696 (under ACG Regional Carriers). Now what, if anything, is different between the different firmware numbers... I've no idea.
Finally, according to this post
http://forum.xda-developers.com/showpost.php?p=56803257&postcount=60 the xt1050 actually shares the same fcc number as the xt1060. This is pretty much all the info I've gathered.