Stainless steel muffler- maybe not

I had my muffler changed about 2 or 3 yrs ago at midas or speedy
(can't remember) on a 93 grand caravan. It fell off this weekend. When
I checked it, the muffler itself was like new but the small pipes
leading to and from the muffler were all corroded. I'm wondering if
Midas/Speedy are using stainless steel on the muffler but the pipes
that are welded to the muffler themselves are just mild steel?? If
this is the case, I think they are a rip-off. The clamps that they
used were corroded badly as well. You'd think they would use stainless
steel clamps??

Anyone know for sure if the stainless steel mufflers these people sell
are all stainless??

Steve L.