Congrats on a beautiful Dall Sheep. Its kinda tough to really scrutinize from an internet pic, but from what I see the job looks very good. Ususally the eyes are a problem area for some taxidermists...they do actually have a direction to install them depending on how the mount is done and the direction it is supposed to look. I don't see any bulbus area in the eyes, and they appear to be symetrical and looking oin the proper direction. The ear, neck, hide, etc. all look very, very good. But, like you said, the mouth seems odd. I don't see alot of sheep mounts, but from the from pics, the mouth appears to open slightly. From the 1st side pic, it really stands out ot me, but it is a natural pose. Personally, I wouldn't call it anything that I would be upset about, its just a feature of your particular ram, just like the slight coloration of the hide. I can only say that because i don't know what it looked like specifically in the field. As was stated earlier, compare to your pics and see if its a mistake on the taxidermists end, or if its acurate.
Either way, great mount, great ram!
PR