The Rules are below, but actual lights seen will depend on the size and rigging of the vessels.

Rule 24(f)
Provided that any number of vessels being towed alongside or pushed in a group shall be lighted as one vessel:

(i) a vessel being pushed ahead, not being part of a composite unit, shall exhibit at the forward end, sidelights;

(ii) a vessel being towed alongside shall exhibit a sternlight and at the forward end, sidelights.