Help with TOAST Compression

I have a table where I store email, the bodies are mostly kept in a
toast table. The toast table is 940 Meg in size. The whole database
is about 1.2 Gig in size. When I back the database up using pg_dump in
custom output mode, I pipe the output into gzip. My backups are only
about 600 meg in size. From this, I assume the that toe toast table
isn't getting compressed.

I am keeping the bodies in a column of type "bytea".

Is there any way I can tell for sure if the messages from this column
are being stored compressed? I know I can set the compression settings
using the "ALTER TABLE ALTER SET STORAGE" syntax, but is there a way I
can see what this value is currently set to?

David