Sometimes you may end up with a small stag without a shield. The important thing is when you mount it to get it right side up. Look for the newest frond and put it straight up. It isn't necessary to have a shield frond to mount it. Just run your line back and forth fairly close to the rhizome (growing tip).

After reading houstonpat's post, I think I'm in trouble. I purchased a stag from a local source. It was in a plastic pot and consisted of two stags growing in opposite directions, with the shields sort of butted against each other. When I mounted it on a wood slab I suddenly realized that I was going to have a problem with how to orient it. Ended up doing it vertically, with the stag with the shorter fronds pointed upwards, and the other downward. Is this a big no-no? It looks rather interesting the way it is, but do I have to take it all apart and redo, and if so, how do I deal with the two? Can I still put them both on the same slab?

The situation observed by maxmom is quite common on stags grown by tissue culture or spores. Usually if they are real close, one will dominate the other eventually covering it up totally. If you find that you have mounted a stag with the new growth pointing other than up you can simply re-orient the board putting an eye screw at the 12 o'clock position or drilling a hole at the top. Otherwise you can cut it free of the mounting and re-orient it. If you leave the tip pointing other than up it is very possible the rhizome will twist around into the upright position on its own.