These coins are magnetic, and the inner disc looks like stainless steel. The inner disc is often rounded on the edge on the reverse, but some are rounded on the obverse or difficult to distinguish. (This possibly has to do with the way the dies and blanks are loaded or cut) Every specimen seen so far has the edge inscription (readable) HEADS-side up, whereas on the reboots (seen at the bottom) it's always TAILS-side up.
There appears to be a resurgence of this fake type. Year 2000 & 2002 have been seen so far.
Main differences are between the two motto fonts. More noticeably the A's, D's & G's, plus the reboot has finer milling.
Detailed edge inscription comparison can be seen HERE