If you want to go for the ROTJ you can use black boots like mentioned in the current CRLs, see below
Boots
For 501st approval:
Black, texture-less, leather/synthetic leather (non glossy) “Jack†boots", squared toe (rounded toe in ladies styles are acceptable), with a relatively conservative heel, no visible straps/buckles, or ornamental stitching; that reach high enough to cover the wearer's ankles are acceptable as a minimum due to the difficulty in acquiring red boots.
**OPTIONAL** Crimson red suede boots, pointed toe, with a relatively conservative heel. There are no visible straps, buckles, or ornamental stitching. The boots cover the wearer's ankles.
Otherwise you prefer the red boots go for that http://www.imperialboots.com/product/guardian/