I assume it's a Sanwa stick as it's a full priced HRAP like the original HRAP I bought in 2005. I didn't buy the Tekken 5 stick back then because it didn't use a Sanwa (the Japanese v ersion did, but the US version didn't) stick but I haven't been able to find out any info on this one in advance so I took the risk as I need it to play the game with anyway, as I can't go back to using control pad for Tekken since I switched years ago. As long as the stick is a HRAP branded stick then it should be using Sanwa stick. The US Tekken 5 stick was just a Hori stick instead of a Hori Real Arcade Pro and that didn't use a Sanwa. I looked on a different forum just now and found out that the Tekken 6 HRAP uses quick disconnects for the buttons.
That's also why I didn't pre-order the game itself as there wasn't any point for me playing without the stick.
I know that the wireless sticks that come in the Tekken 6 collector's edition boxes do NOT use Sanwa sticks.