On Sat, 19 Apr 2014 11:50:02 -0700, "Julie Bove"
wrote:

There is another hole. It is an overflow, I think. I am interested in the
pulldown sprayer but not sure how problematic they are.

You can remove the air gap vent on top of the sink and then use an
under sink solution. The air gap relates to the dishwasher/drainage.

Pics

http://www.askmehelpdesk.com/attachments/plumbing/16988d1235612177-newly-chronic-overflow-dishwasher-dishwasher-air-gap-installation.gif

http://www.askmehelpdesk.com/attachments/plumbing/29993d1269632734-dishwasher-overflow-vent-sink-required-high-loop.jpg

Then you can use the hole for a sprayer.