At the top of the card it just says Attack (Target Lock). Many missiles instruct you to spend the target lock to perform this attack, but this one does not. Does that mean you simply have to have a target lock on a ship to perform this attack, and you can use your TL for a re-roll? Thanks in advance guys.

Exactly right - same goes for Homing Missiles

You can use the TL for a re-roll but you don't have to. You may keep it for next round.

You have to have your TL ON THE INTENDED TARGET of your IPM.

As they already told, anyway, you don't have to spend it to launch them and you can use it to modify you roll