I wonder if this example will make sense, but I liken it to Republic Y-Wings vs. Rebel Y-Wings. While the basic shapes are the same, the surface details given a different impression.
Great example. The Republic Y-Wings look like they just came off the assembly line. Meanwhile the Rebel Y-Wings look refurbished and retrofitted. But with good reason. The Republic had the means and facilities to repair them to look like new while the Rebels probably didn't always have access to high tech repair station so they had to jury rig, cobble together and practically do what they could to keep their ships running and in working order.