Alucard has more options to win, but there is still potential for stalemate. Captain can easily react to bullets and he can mist-shift to phase through them. Once he gets close enough, he can reform and destroy Alucard's guns, depriving him of silver.
Cap can't kill Alucard, and Alucare can't kill Cap. The result is a draw.
Impractical, in both cases. As a werewolf, Captain's attacks are mostly blunt and someone with as much durability and endurance as Alucard can take them. Even more so since he can shift into mist and shadow energy.
How is Alucard going to penetrate through Cap's werewolf flesh enough that he stabs the heart, which Alucard doesn't even know the location of since he has limited knowledge on werewolves. Knifehand attacks and shadow spikes aren't going to do it. And captain can shift into mist to avoid Alucard's attacks.