There are no "tang options" on a five. I'm not even sure what that means. Model #1,#2,#3,#4,#5, etc. "all" have cut down tangs. The Model #14, #15, #16, etc. have full, exposed tangs???
Duralumin or brass butt caps on anything besides a leather handle (Or a #25 style handle) is an option.
Hope this helps. A cut down tang simply means a reduced size to allow for handle material to be "sleeved" (for lack on my part of a better term) over it, allowing a 360 degree encirclement of the tang and thus showing nothing but handle material.
Capt. Chris