BuckarooKnives@BuckarooKnives we have been oiling the tan leather to demonstrate how it darkens. I'll try to add a few photos here for you to take a look at. I would say most customers have opted for a breathable waterproof spray to preserve the lighter tan.
BuckarooKnives@BuckarooKnives here's a comparison photo with the boot on the right having two applications of oil (Huberd's). A slight darkening and it gives some more character to the tan leather. This will be more pronounced as the boots age and additional oil is applied.