Mike and Walter, I can not say for sure as I do not have a picture of the Spangler engraved Optimus gun made for President Harrison. Once we have a good picture it should be easy to compare other guns engraving. His dogs were described as almost life like.
DrBob has a few Lefevers done by Glahn that are signed, and with his permission, I will post them for comparison.
Mike's looks more to me like Glahn's, and Walter's is tough to say, but they are nice dogs.
I had taken a high resolution picture of the picture in "Steel Canvas" (I hope I didn't do anything unlawful). As you can see the resoulution is not good. The picture in the book was only maybe 2"x 3". I believe Spangler signature is under the pointer's legs.