You got lucky! Those bags look like they are in great shape.
I have a set of these exact Krauser bags.
So it looks like the clasp that lock the bag to the frame has a keyed lock, which should be much more secure.
Near the key opening there should be a number. With this number you should be able to order you some keys. Krauser keys are/were made by Sudhaus. They are short keys.So they do lock.....
now I just need the key's.....
Back to the original owner I go.....or order them from BMW