3-6 monthh most times is not a problem but cant count on your taxidermist getting to it rite away ,by 9 months or so
the is a much greater risk of requiring repairs from dry ears while turning so if ya need to freeze long term it would be better to have skined & tanned for future mountin
Wrap it up good in a substantial plastic bag, get the air out and seal it up. I will be mountable for a long time depending on the packaging. A long time meaning a year or so, but it is best to get it taken care of properly asap.
i also heard that its depends on if you have a automatic or manual defrost freezer, the manual freezers dont shut off to defrost like the automatic ones which turn off every so often to defrost the ice build up. my taxi told me that you can keep them stored longer in a manual defrost freezer.