Fusible link on 65 c10 from battery?

[mrdave03]

I had to replace the red wire running from the positive battery post to the junction ( horn relay) just before the voltage regulator. In my diagram in the repair manual it does not show a fusible link near the battery.. nor was there one prior to me rewiring. Yet I see many threads speaking of one near the battery in the red wire. Was this something added on 67 and later c10's? I'll try and post the diagram to show what I refer to.. I see on previous threads diagrams posted with one installed.. I'm confused...

Also the original diagram for the 6 cylinder (In my manual not the same as posted) showed a red #12 wire battery to horn junction. I since upgraded to a small block 327 so I upped the wire to #10. Does that seem plausible?