I have not prepared steak tartare with anything I have dry aged but I have eaten the meat raw as i have been dressing my dry aged rib eye etc. it tastes fantastic (to me anyway) and i can not see any reason why you could not prepare tartare with it. Frozen will not be as good as fresh, but if it has been handled properly it should not make you crook. I have recently dressed cut up, and put in the freezer a full boneless rib eye, and I would not hesitate to thaw and make tatare if i got the urge. Ultimately it is up to you, I don’t want anyone saying Chris made me crook.