Yes, a Series 79 exam is one of the prerequisites that must be taken before passing a Series 24 exam. You could also obtain an SIE and a Series 7, an SIE and a Series 57, an SIE and a Series 82, and an SIE and a Series 86 and 87. You could also forgo the SIE and a complement and sit for the Series 16 as a standalone prerequisite. If you have only the Series 79 and the SIE, then the principal registration you would be able to acquire would be Investment Banking Principal (BP).