Go to montanavintagearms.com and confirm that you have a 107 or 108 model and see what they are worth new. Then price it accordingly. That looks like "as new" to me, so maybe 75% of new would be a good asking price? Front globe depends. With a level or not matters to many.
I'd stick with that particular tang sight however, though I've been told it doesn't work very well. A whole lotta dead critters disagree however...
