I am left-handed. My only cap lock rifle is a L-H Lyman Great Plains Rifle .54-caliber. It weighs about 9.25 pounds. So much for bona fides.
If you acquire a L-H cap lock, you will find it difficult to sell if the woman decides to not shoot. Since you have limited your universe to CAP LOCKS, maybe you should consider a R-H lock. If she likes shooting, you can always start your search again. If she does not, your out-of-pocket cost has been substantially less. And your ability to sell the rifle is improved.
Although I would not want to shoot a R-H lock, I have L-H several friends who do without complaint. It is neither unsafe nor slower. It just looks clumsy.
Note: in the universe of L-H rifles, I recommend you consider building a kit gun -- for example from Track of the Wolf -- if she becomes dedicated.
Lymann GPR would be acceptable as cap lock. Avoid the flintlock version like a foul smell.
Hope this helps.
