Yes these are prototypical I've seen #4681 I believe back in 2007 and I didn't know why it didn't have a white roof top. The second one #4689 was a leased unit from EMD that was also repainted later to CSX YN3 with no white cab top. But I assume that these where the first YN3 paint scheme where they didn't have the white roof cabs. You can do a search and see pics of both units.
