Drat, I thought I had found the EX1 mag I needed. Later I'll post the same photos as you show above, except with the X8 mag.

There are EX1 mags about yet. The majority of the EX rifles were given to cadet units for drill purpose, and many of the mags were retained as souvenirs. I'm pretty sure I had a couple as well, way back before I knew or cared what they were.