The MD301LL/A is a newer Navy Leather case that they released more recently (late last year I think and not specifically for the new iPad launch) ... The MC947LL/A is the older model.
The MC947LL/A has a bit of a greyish/blue tint to it, while the MD301LL/A has more of a royal navy blue to it. Check the link below for pics and comparisons.
https://forums.macrumors.com/threads/1284303/
Wow, good catch...I really like the current Navy Blue that the Apple Store sells...UGH thought I would be saving 15 dollars, haha.