Yes, because of its recon camera.
The rules for indirect LRM fire (TW p. 111) require a friendly *ground* unit. A Boomerang is not a ground unit. However, an air unit with a Recon Camera (TO p. 338) can spot for indirect LRM fire. So, because a Bommerang has a recon camera, it can spot for indirect LRM fire (in addition to artillery indirect fire).
A Boomerang can spot for indirect artillery fire (TO p. 181) as artillery spotters are only referred to as a "friendly unit" with LOS; there's no mention of a ground unit requirement.
