All original with diesel? I did a little research and there is a rumor that a few M-38A1s destined for export had diesels in 1952 (http://www.willysmjeeps.com/v2/modules.php?name=Forums&file=viewtopic&t=4725). If that really did happen, then I suppose it is possible that a M-38 could have had one installed as well. However, I have seen no other evidence to support this.
“Testing the waters with this all original 4 cyl. diesel.”