In the 7 years that I had a spinnaker on my cats I have never had an anodised spinnaker pole. It will hold up nicely. What happens is that it will turn dark grey and loose its shine and when you rub it hard with your hand then some of that drak grey colour will stay on your hand but that is all. I used monel rivets and stainless steel bolts on my poles and didn't use any isolator but the galvanic corrosion is so slow that you probably can use it for 10 years before the bolt/rivet holes wear out and you have to reposition the fittings.

Wouter