I've also been trying to find examples of the 70's 6.5" Vistalite snare drums. There's just not that many of them and, those that I've found have been single color, not multi-band color. So, yes, the drum in question does appear to be on the rare side.
What is the depth of the top and bottom panels? If they're each the same depth, then this is probably a case of measuring issues from the start. Let me know those depths.
-Mark