Long Manufacturing designed and built the 150, 250 and 350 balers for Ford, and later designed the 530-Series, sold the design to Ford, and Ford had it manufactured elsewhere for them. Documentation that I have does not indicate who manufactured, so it could well be NI. Long also sold the 530-series under their own brand name for some time.
My 532/542 parts manual indicates that the knotters are identical for both of these models, and I believe those on the 530 are too. The 350 may also be the same. However, the 250 knotter assembly is definitely different.