It doesn't look like an undermount. Did you look at the additional pictures?

For that price, I'd want 16 gauge, not 18 (thinner).

Another possibility for unusual sink sizes is Julien. They are $$$ but their 24' is recommended for a 30' cabinet. They come in 8' and 10' depths. Their drains are offset to the back. I had the only one that I could retrofit into the shallow cabinet and loved it after I got the grid.

Too bad Kraus and Ticor don't have the right size with offset.

Here is a link that might be useful: Julien

agree with the 16 gauge recommendation. It looks like it could be undermount to me, but it will be very deep, around an 11" deep sink. Would that be comfortable for you? I have a 9.5" deep overmount and I wouldn't think I'd like any deeper. I have a C-Tek Sink that is 16gauge that I am happy with. It happened to be an overmount or undermount style.

Further down the page, the Dawn sink does say "Style:Undercounter & Tile-In." A number of other pages list it as a dual-mount, but I did not find installation instructions

Elkay makes one that will fit in a 30" (see link)

Here is a link that might be useful: Elkay Elumina

The Elkay is only 18 gauge also. Could you give up the offset drain? Is that an absolute necessity?