Here was the quick response from Canton. I am very impressed!

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Dear Mr. XYZ,

Thank you for your questions about the GL-260. The GL-260 was manufactured between 1983 and 1989. For stand mounting, the LS 80 stand set would be compatible with your speakers as they include 2 M 6x12 screws for mounting. To mount them on the stands, it would likely be a vertical set-up. Finally, we unfortunately do not have manuals available online, but the specs for the speaker should be printed on the back.
Thanks!

Sincerely,
Amelia ...
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Now, there is no way I am springing $175 for those stands when the speakers cost $115. Does this email suggest that the mounting hardware is fairly common?

Thanks.