I think you could put together a Spicer joint by buying two and swapping caps, but there's no point since JPaul found the answer! Part of the problem is that all the online parts dealers used to have excellent exploded diagrams and part numbers for just about any GM vehicle. Now they almost all suck. I used to use GMPARTSDIRECT.COM to look up parts even if I didn't end up buying it from them, but now there parts search sucks. Nalley is about the best left and it's not as good as it used to be.
A little more background of why I was searching and a couple things I learned. Even though I said initially I wasn't looking to debate greaseless vs. greased, I have personally found no real difference in the two as far as longevity, and if it saves me from crawling around and having dirt and grime falling in my face every few thousand miles, I am all for it. Just as a bit of "proof", my H3 still has the original U-joint at the TC on the rear prop shaft. It is greaseless and now has 290,000 miles on it. I agree, that's not normal for any joint, but kind of says to me being greasable may not be as critical as some people believe. Opinions vary, and that's cool.
The dust boot on the CV finally bit the dust and I got a really good deal on the whole assembly that it didn't make sense to buy the replacement CV. It had been on the shelf still wrapped up for a couple years and I assumed it was a greased U-Joint since that's all that seemed to be available. I intended to replace it with a greaseless one before I put it in. I unwrapped in and was pleasantly surprised that it was greaseless. When I went to put it in, it was about 1/16" too wide on one axis. I figured there was probably a needle bearing in the end of the cap. There was, but still another was missing. After digging through the grease reservoir, I found the last one and put it back together. Was not happy with the quality control there, but at least it wasn't something I had to try to explain why I needed to return a part I bought two years ago. What I DID find, is that the needle bearing in the GM joint are considerably smaller than in the Spicer. Does that mean it's going to be less durable? Who knows. Assuming the caps are the same thickness, it's possible the GM cross is actually larger. Really don't know. I wish I would have measured the two, but didn' think of it until after the fact.
Anyway, thanks JPaul. Appreciate your finding that part number. Just out of curiosity, how did you find it? I searched for 2008 H3 on Rock Auto and it did not come up. Did you search a different year?