2 matching wall sconces

We just purchase a home that was custom built in the early 1970's to resemble a swiss chalet. These 2 sconces are on both sides of our master bedroom fireplace on the third floor. We need more light and my husband would also like to replace them with a flat screen tv. I like them but do not know if they are worth keeping. They could be crystal as they do have a rainbow of colors in the light from the french doors in the bedroom. They are very dusty as the home has been vacant for over a year. I thought that they would match the bedroom better if I painted them black, but do not want to ruin them if they are valuable.

Good