Westland, yes and no, i think.

For some units it might be advantageous to get the AI to specialise. For instance, it might be a beneficial for the Italians to have a province that specialises in Italian Infantry for example.... just to get them to build them

Likewise, to promote shipbuilding in certain provinces it might be an idea to have a provincial bonus there, as when a province is specialised there's more of a chance that they'll build the units you want as there won't be such a choice, e.g. ships from Venice and Denmark.

One word of caution with this:

When provincial bonuses for ships are applied to a province with no starting buildings the AI seesm to get stuck at a port and fort and doesn't go further than that. This is what happens with the original Tunisia, which has +1 dhows. The Almos build a port and a fort and then no more, not even the gold mines.

EDIT:
By removing all bonuses the AI will simply follow the normal building priorities as dictated by the Build_prod file. I assume it'll also follow any special build combos from column K?