Shimano FD-MC34 front derailleur. Triple?
 

So I sold a front derailleur on Ebay. A shimano FD-MC-34. The buyer wants a return and says it's not a triple? He claims it's a double. I mean really. It's a triple. is there any official documentation of this? Thank you. .
https://cimg5.ibsrv.net/gimg/bikefor...392460cfc6.jpg
https://cimg6.ibsrv.net/gimg/bikefor...8f61debe2b.jpg

Here's a document showing it's a triple FD:

https://si.shimano.com/pdfs/si/SI-F520A-000-00-ENG.pdf

I think every non-junk mountain bike of that era was had a triple FD.