I can't find anything as convenient as a "schema version" in my databases.
Perhaps you could:
- download 1.75
- locate the sql upgrade scripts, to identify the schema changes between 1.74 and 1.75 (or download both 1.75 and 1.74 and compare the sql scripts to create new databases)
- look for the new data items in your db: if you have them, you're at 1.75; if you don't, you're at 1.74.
...or, (perhaps simpler) - attempt to "upgrade" to v1.75 -- if the upgrader does something or not, you're done.