Postgres reported table / db size varies wildly from dump size
Note that unless your application is going out of its way to use the large objects interface, then it is not storing those columns as LOBs. Normal columns can store up to 1gb using TOAST (The Oversized-Attribute Storage Technique). 

In addition to storing the data out of line, it may be stored compressed. Although you don't say so I assume the dump you are composing with is uncompressed, which could account for most of the size difference.