Generator swap to internally regulated alternator

[62stepside longbox]

I am in the process of replacing the generator on my 62 with an alternator. I believe it's a Delco remy 10si. I have already figured out the mounting but my question is about the wiring. On all of the 10si wiring diagrams there is a diode wired in between the terminal #1 and the ignition switch. Do I need a diode or will the charging light in the gauge cluster work as one? Thanks. Here are some pics of the alternator mounting brackets