I've installed the Trijicon AR15 front sight on my AR180B, and it works fine - and, yes, it does allow the "lamp" to rotate for more precise zeroing. The front post is nice and square, just a smidge wider than the GI post, and it gives a nice sight picture in daylight, while the dot shows up very well in low light.
Although the XS Sight Systems sights with the white vertical stripe and tritium bar give a very quick, precise sight picture at speed, they don't allow the lamp to rotate; XS rationalizes this by stating that you'll be no more than 2MOA off from your point of aim no matter what. I don't particularly care for that, so I went with the Trijicon unit. That said, I have XS sights on my SAR-2(AK74-type) and my Marlin 1894, and like them very well.
Meprolight also makes a striped front post with tritium bar, that rotates like the Trijicons; I went with the latter because I've always had good results with Trijicon pistol sights, so they have my personal confidence.
