I recall the US ban on sealskin. The sporran makers started making some really tacky and tatty looking rabbit-skin sporrans for the US market. They didn't look half as nice as the sealskin ones.

I suppose if any ivory pipes also have sterling silver mounts that are hallmarked, that could perhaps be persuasive when it comes to the age of the instrument, although when I worked for two bagpipe makers back in the 80s, I saw a fair few sets of vintage pipes that were mounted in sterling silver but which had no hallmarks.

One of my own sets of bagpipes is mounted in Britannia silver (purer than sterling) and were made in the 1890s and yet not one of the mounts is hallmarked.