Yes, but there SPQ-9B is not described as a surface radar. It replaced an radar used for gun fire control (SPQ-9A, also not a surface radar!), but it has now more functions - not only the capability. You also had mentioned that it is also for detecting and tracking of anti-ship missiles and low flying aircract. This is part of the fire control, but not only for guns, but also for ESSM etc.

SPS-73 - also (V)18 - designed as a surface radar. There are no descriptions that this radar is for detecting or tracking of missiles. Therefore, I think that these two radars have very different tasks.