Yeah, it wasn't until the next series of BH they went to the bolt-on teeth. I wonder if you can update the bucket if the weld-on tooth is tough to find..?
The tooth part you found is likely the bolt-on for the newer bucket. There may be some custom fabrication needed to make it work.
I have the same bucket and am designing a "clean-up edge" to bolt-on over the teeth for ditch maintenance work.