[tigertone]

I know this is an old post. I was wondering if you ever found an answer. I had the same question. One thing I have seen is that all original shrouds, doesn't matter which engine, have a raised collar formed in the metal on the end where the duct slips over. I noticed the reproduction ones do not. They do not have this feature, it is smooth and the duct slips over much easier. In the photos the black is the smooth connection.The other pic , cad plated one, has the rolled raised edge. Hope someone can help verify this.