Does the repeat of Called Shot count as a second card played?

No, the Repeat effect of Called Shot does not count as a second card played.

According to Rule 746.3.a: "Regardless of the number of times a spell's instructions are executed with this keyword, the spell is only Played once."

When you use Repeat, you are paying an additional cost to execute the spell's instructions an additional time, but you are not playing a second card. The entire process occurs as part of playing the single Called Shot card.