to update this thread:
as a result of the reveal of the new major Swiss collection (the Jolina Gisele collection), it appears that at least one of the Jigglypuff PSA 10s can be confirmed glossy. IIRC, I believe this means that this copy (cert: 25603184) is the only confirmed glossy 10 in the world.
However, the PSA 10 Pikachu in the collection is the non-glossy version. Cert #26639080 has been deactivated by PSA (I believe this was mentioned earlier in the thread.)
(both images come directly from the Swiss collection’s Instagram page.)
Does anyone have more updates/insight to share about this topic since the last post two years ago?