I just went through this ordeal myself.
Q:How Do You Turn A 30 Minute Job Into A 13 Hour Nightmare? 1986 300SDL

My decision to replace the entire alternator was more difficult than yours should be. I got lucky and found my rebuilt Bosch alternator on sale for $165.00. I figured since I didn't know when it was last replaced, or how long the vehicle had sat, it wasn't worth spending $30 on a regulaotr, only to end up having bad windings, a flat spot, etc.

I just looked up your alternator and it's $98.00.
That makes it a no-brainer as to whether you replace just the voltage regulator for $25-$30, or the whole unit for $98.

Hope your install goes smoother than mine.

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1986 300SDL
1988 Monte Carlo SS
2002 Avalanche
2003 100th Anniversary H-D Dyna Wide Glide