You can check for the FRU numbers on the IBM website, though I'm not totally positive where the link is. Here is the FRU number for the Thai keyboard: 08K5044 This number is for my 14.1 inch T42, so I'm not positive if they are the same for you, or what size you have.
I have heard the differences described as night and day, so I too, of course, wanted to experience the orgasmic tactile difference...
Mine just came today. It's sort of ironic, because as the UPS guy handed me my Thai keyboard, he took my T42, because it turned out to be an expensive door stop.
Anyhow, now I have this great keyboard, with nothing to stick it in, until I get a computer back.
First impressions? Definitely nicer. The trackpoint buttons are MUCH quieter, and the keys feel sturdier and harder to push in. Overall I think it will be a nice improvement.
EDIT: Oh yeah, I forgot to tell you how easy it is to get the Thai keyboard. I called IBM the other day, and told them that my keyboard is kinda clacky, and a bit loud, and would like a new one. I gave him the FRU number, and he said it was in stock and they'd send it to me. And here it is...