I've done many plastic faced sign replacements and all have had a simple retainer at one or both ends that unscrews and the panel slides out. This sign has a rectanglar box, with a 2 x 2 square frame all the way around. It appears to maybe be set on a lip at the the bottom with small metal screws in at an angle at the top edge to hold it in place. I am guessing the entire rectangle must be removed by taking out the top angles screws and tilting it out. Then, the panel must remove by loosening the miter joints or some bracket on the back side? Any advice is welcome. Just trying to figure out if I can do this face swap in one trip or if they need to be removed and back to the shop. The sign is only 15 years old, if that matters for style. Thanks.