No I'm not sure. They are tiny, but maybe they're just young. I got them at PetSmart and they weren't labeled as dwarfs (never heard of that). Are they usually that small when you get them because I've have seen other corys that are HUGE compared to these?
I've got 6 of these guys. Great fish. The largest three were in my original 20g and I've had them about a year, the biggest being roughly 2.5 inches. I consider that to be as big as it will get. Actually it wasn't until I moved them into my 75g that they really started to grow out and show their true personality.
The other three were new additions to my 75g when I set it up last November. They were about 3/4 inch at purchase and are now about an inch long.
when I originally got my 4 corys they were all around 1" long and a year later the biggest is almost 2". I dont know if I've stunted mine or something, but from what I've seen in my tank and others corys grow really slowly compared to most other fish. I've seen some huge bronze corys though, in excess of 4".