Blacktail,
I have never hunted it myself but have hunted Unit 11, just to the north of Unit 13. (Whitebird is in 13 and I am assuming the land you have permission on is in that unit also, correct?) I have also been in that Unit many times just visiting friends or moving through.
If I am not mistaken, Unit 13 over the counter tags are Whitetail only. To hunt Mule Deer you must draw a CH tag. I'm sure that if you are just hunting for a buck and don't care about the particular species then you should be golden. I can tell you this, I drew a CH tag for 11 and hunted the land along the Salmon river. Directly across the river was Unit 13 and I saw quite a few VERY nice bucks in those river breaks. In fact, there was a camp of three folks on our side of the river during that trip that drew Unit 13 tags. They were taking a small boat across and hunting those very breaks every morning. They all tagged out on three impressive animals.
What info are you lookin' for inparticular? I have a friend that lives in White Bird and owns a cattle ranch. I may be able to get additional info if you can elaborate on what you are lookin' for.