I know that the first matte crocs came out around the late 1990s - year 1999 or 2000 something like that. I remember Hermes only had about 4 colors in the matte crocs and all are lined in cotton/linen. (rouge h, anthracite, havane and indigo blue)
If I work back, mid-to early 1990s sounds about the right time when H made birkins with crocs. But am leaning towards mid-90s ...