The issue of sealskin sporrans has been discussed here in at least one, if not two or more threads. One of the members here is with US customs. The info he gave, as I recall it, was that not all seals are endangered, thus some sealskin sporrans are quite legally imported into the US. However, most customs inspectors probably can't spot the difference on site. I don't remember any discussion of the date of the sporran having a bearing, but it may have. If you use the search feature, you can probably locate the thread(s).

Hope you have an enjoyable trip to our shores. Have you thought of a kilt night of X Marks members at the locale you are visiting? I am sure quite a few would like to meet and welcome you.