Trump in 2000 was trying to be the next Perot. I'm pretty sure the views and beliefs he espoused then are much closer to how he really thinks. Of course, he wasn't actually trying to run for President back then so he didn't need to pander, IIRC in 2000 he had a book coming out and wanted to promote it.
I do think he's more serious about running this time, but I don't know if his birther talk is an effort at pandering to the wingnuts because he actually wants the nomination, or if it's just some sort of elaborate troll.
Well, if it makes his supporters feel better, Trump 2000 was still more conservative than McCain 2000 and Romney 2000.
The best part about his little tax proposal here (which is an interesting idea) is that this was pre-Bush tax cuts and during a surplus.