Collectible and valuable are two different things... But that said, a similarly-restored 67 K-code would probably bring about as much as a similarly-restored 68 GT350
A similarly-restored 67 GT350 would bring yet more money, as they're in stronger demand, even though the rarity-nod goes to the 67 K non-Shelby.
The 1968 GT350 does not pull as much value as the 1967 GT350 because the J-code 302 was not much of a runner, and that's putting it as politely as possible. Ford fixed that issue in 1969 with the introduction of the 351 Windsor...
I agree with dalorzof's value estimates for restored cars, assuming the restorations really are top-drawer, but I think good projects could be found for less (maybe not for the convertible, but for the fastback).