Are you asking if the heel be replaced if the heel will still be waterproof or if the boot be waterproof. Either way, the waterproof guarantee will not be valid if you have the heel removed. You would need to have another treatment put on the boots anyway, since the waterproofing usually lasts a few months anyway and you would need to continue to have treatments done to maintain the boots integrity.

If the 20% coupon is from Sheplers, then it may work in the promotional block or if unsure call into customer service and give them the code via phone.

Usually when a manufacturer produces a boot and offers it for sale they will offer it in a series of colors, if the color you require is not available when ordering most likely it is not available. You can try to call the call center and put in a request for that color, otherwise, what you can do is to take the boot to a shoe repair and have them strip off the finish and change it to black for you. Also request that the waterproofing be reestablished for the integrity of the boot. Also note once you modify the boot, any warranties or guarantees set by the manufacturer or by selling agent are null and void once tampered with. Also check with the repair facility prior to purchase to find out if they will honor such a request to change a color of a boot.