Re:
I contacted seller and asked about cracks (thanks to Google Translate, as I don't speak German), and I included my composite photo of an ACX that I posted earlier in this thread.
Seller's response:
Vielen Dank für die Fotos!
Der Rahmen hat tatsächlich an der Schweißnaht unterhalb des Sattels einen feinen Riss.
Translation from Google Translate (for the uneducated, like me ):
Thank you very much for the pictures!
The frame actually has a fine crack at the weld below the saddle.
I messaged seller again indicating that they should include that info in the auction description, as well as a pic because
1- it might get returned, and
2- it's a safety issue.
Naturally, I asked them to consider me if they have trouble selling it, and that I would make them an offer (even though I live in USA). If I'm lucky enough to acquire it, I'll be taking it back to my Young Frankenstein laboratory and throwing it onto the pile of cracked ACX's, and eventually breathing new life into it. When I'm done with it, it won't look original (which is probably a good thing), but I'll get it back on two wheels!