Sterling refers specifically to an alloy that is 92.5% silver. If the mark on your piece denotes its purity, it is 96.5% silver, so it has a higher silver content than sterling, but is not pure (99.9%). It will be softer than sterling, but not as soft as pure silver.

What is the piece with the mark?

Nothing of big consequence, it's a key chain with a St. Christopher Protect Us medal. On the latch is the image that I've shown. I may be way out in left field, but I noted on Worthpoint that there was an item with the 965 + MAD marking and they said that it was sterling. Still in the learning curve about all things silver - LOL.

I went to a silver auction near Baltimore a couple of years ago. Among the things that I looked at was a large, about 14" metal plaque marked STERLING. It was inscribed with about a dozen doctor's names in Spanish. Something bothered me about the plaque, it simply didn't look like silver. Also, why would a plaque to hang on the wall (in a doctor's office) be made out of something so valuable? In hindsight I think it was nickel, using a magnet wouldn't help because magnets won't stick to nickel.
See link about Mexican Silver Scam.

Here is a link that might be useful: Mexican Silver Scam

I believe "Sterling" is a mark used in only a few countries, probably Britain and its former colonies. "925" is a much more common mark and I would expect it to be used in Mexico.

Grab something you know is sterling, rub it hard with your thumb, then sniff the thumb. Do the same thing with your medal. Do they smell the same?