From what I've heard, Lyman only sells gas checks of the Hornady pattern. I don't know if the old style checks are "collectible" but they are still in demand from some shooters.

Xausa, I've had the chance to try the tools sold by Patmarlin. Of the various tools I've used to produce gas checks, his press-mounted set-up is the easiest to use and most consistent. The end product isn't "the same" as the old-style Lyman checks, but accuracy is similar. My pet load in my good Krag shot a little high and left, but group size was as expected.

I'll probably purchase a set in 9.3 sooner or later. Gas checks for the 9.3 are currently available, but being it is a non-standard size in the US I don't trust that they will "always" be available.