My Home course is par 72, 6200 yards, 68/109 (which is being recalculated this year due to upgrades).
I think a pro would shoot under par. Heck, every so often the best golfer in our league shoots a-1.
However golfers in our league have played the course a couple dozens of times a year.
If the pro were to only play the course once, the 2 things that would affect their game would be:
1- the greens. They are some of the most difficult in the area. They have multiple breaks, they are fast up hill and slow down hill. They always break towards the river, no matter what you see!
2-I think a pro might be a little out of their element on this public course. Hole #1 runs along side a road, and the cars may honk in your back swing. People have been known to scream at you. Since the course is a also a public park, neighbors can be found walking (or walking their dog) along the cart path or even across the fairway!