hmmm. I had a look in uc_catalog.module. The only theme functions I see are...

theme_uc_catalog_block_start
theme_uc_catalog_block_end
theme_uc_catalog_browse
theme_uc_catalog_special_products
theme_uc_catalog_bestsellers_products
theme_uc_catalog_products
theme_uc_catalog_item

That's everthing that was turned up when I searched for "theme_"

I'm using 5.x-1.0-beta2

There's a slight chance someone else who worked on the project may have modified the file, but I think probably not.

-Ryan