Blue Book, Possible Misprint

Could well be. Red Book is typically high retail, Blue Book what you might expect a dealer to offer you for such a common item

with Frog

Also consider that Mint State usually is listed as MS-63 in the Red Book for example, so that is a good example where condition values can be slightly misleading if you have a very high grade example that in this case can be conditional rarities (finding them in that top condition is rare) and have higher values accordingly as BStrauss3 mentioned. So if you are using the blue book for general values to sell to a dealer wholesale just be aware that there are exceptions even if that price is potentially accurate if there are plenty in that lower mint state grade and dealers are overstocked it doesn't apply to much higher grade conditionally rare examples.

This is somewhat incorrect. All uncirculated Mint set coins — which includes the 2014 high relief issues — are minted at slower speeds, with higher pressure and fresher dies, and given better care in handling than the normal business strike run. I said "somewhat" because even with that, you are still not guaranteed a gem example.

Also, starting in 2015 all uncirculated Mint set Kennedy half dollars are high relief, which like 2014, makes them different than the ones offered in bags, rolls, and for circulation (when released).