Decal Girl installed on front of your reader slight different corner radius and thickness shouldn't matter. For leather cover depends on retaining system details. Moulded plastic retainer sections are not very forgiving about slightly wrong fit. Slide your reader into leather sleeve with screen opening and book style hinged cover or with corner retainer straps maybe a little more forgiving.
Order a cover from Gecko Covers and they tell you if they make a cover for your reader and which one would best meet your needs.
http://www.geckocovers.com/ereader-covers.html