Yup, many quality ice cream places use frozen yolks. Thing is, frozen yolks are ONLY available with the addition of 10% sugar, OR 5% salt. Hot kitchen tends to use the salted yolks for Hollandaise., but I've always had excellent results with the frozen sugared yolks.
I am still a little confused, are the containers frozen when you get them? If not, they will make ice cream fine with no problem. If you plan to freeze them, they will turn gelatinous without the addition of sugar or salt.
edit: oops, I guess foodpump types faster than I do
Not much to risk. I've been using frozen sugared yolks for well over 20 years now, and am pretty sure that product was around longer.
10% sugar to 100% yolks is the general ratio. My packaging states a 1 yr freezer life.