If I recall correctly, the original EMD NW-2s (1940s to early 1950s) did not come with Roller Bearings because these were a maintenance replacement that became available in the 1960s... NW-2s had to be re-greased frequently which is why Roller Bearings with less maintenance eventually became more popular.
I assume that you are looking for AAR Type A Trucks made by GSC which have modified Journal Boxes that open to show Roller Bearings? Do you prefer all-Brass or else cast White Metal?
Regarding 2-Rail O-Scale AAR Type A Truck Kits, you may want to contact Mike Calvert in England... he has cast many different types of very detailed Trucks over the years and may have the mold designs that you seek. He can make the same Truck in either Brass or White Metal, but 260 Brass is harder to cast & more expensive.
As far as cast White Metal AAR Type A Trucks, the only O-Scale Brass Manufacturer I know that used these is Locomotive Workshop (Jan Lorinzen). I have 2 sets that came with my LW ALCO S-4 Kits and they do not have great detail nor do they have Journal Boxes that open...
Regards, Steve
Cincinnati, OH
