Their link to the exploded parts drawing is:
The one I bought is different; it has ceramic stems but when I handled it I noticed that it was so much shorter from C/L to end of the casting than my existing unit; and I realized that if I removed the stem assy, the opening would be behind the wall. And even though the one for sale above has compression stems, the valve body is also short.
So is it standard practice that these short-bodied units will end behind the wall? Or do you cut the 2x4s away in order to move them forwards enough? Is Eljer just a totally unique long length?