Based on the community input, the logo color appears to reflect a newer vs. older production version rather than a fundamentally different lens design. In the examples discussed, the second lens shown is the newer one, and a higher serial number is another way to confirm which lens was made later.

From the information provided, there’s no evidence of other important differences beyond production age/cosmetic variation. If you want to verify a specific copy, compare the serial numbers as well as the exact model name engraved on the lens.