Glen, Yes - they bolted on to the bucket using the existing holes for the removable wear edge. The bolt holes on the teeth are a little bigger than those in the bucket but that hasn't seemed to be a problem. If it ever stops raining I'll try to get a better picture.
From JD Parts the 300 and 400 HD buckets are the same:
BW14764 LOADER BUCKET 1550 MM (61") (COMPLETE GOODS/SHIP BUNDLE)
BW14765 LOADER BUCKET 1850 MM (73") (COMPLETE GOODS/SHIP BUNDLE)
Kelly
From JD Parts the 300 and 400 HD buckets are the same:
BW14764 LOADER BUCKET 1550 MM (61") (COMPLETE GOODS/SHIP BUNDLE)
BW14765 LOADER BUCKET 1850 MM (73") (COMPLETE GOODS/SHIP BUNDLE)
Kelly