Well, turns out they aren't specifically NSN Antennas. Thanks Milan03 for poking me over on another message board, but I've discovered a site that looks like OP's picture here in CSprings.
Most of the sites here look like
but there's one near the house that looks like OP's picture:
So, the legacy panel is still mounted because as you can see, this site isn't completely up and running. They threw this together at the last second just as LTE launched here Aug 1.
So, a few things about T-Mobile panels, lilotimz. Turns out, all the panels in the first picture and the middle panel in the second picture are made by a company called Andrew, which, to the best of my knowledge, isn't affiliated with NSN. I found this out after waiting months for T-Mobile to equipment refresh a site in-county but outside of city limits (none of CSprings records of this type are online).
http://adm.elpasoco.com/Development%20Services/Documents/Planning%20Commission/2013/Staff%20Reports/07%20July/CMRE%20VA-13-004%20Variance%20of%20Use.pdf
Page 23 has the make and model #'s of the panels they're using here in town. I'm still unsure who makes the fat panel you see in the second picture, but it has the same purple triangle marking as all of the other NSN T-Mobile sites here. I'm going to assume it is also an Andrew panel as the connectors and servo motors hanging from the bottom look the same. As for milan03's panel amidst the sea of Ericsson, it looks an awful lot like the Andrew panels they use here, minus the bottom-connectors. While the stickers on the panel are different colours, they appear to be in very similar positions on the similarly-shaped panel, so it could be a different Andrew model.
