I wouldn't touch them, they are now and always
have been junk...
Customers who want to have their locks installed
need to acknowledge in writing that the installer
makes no warranty for said locks... Any callbacks
not due to a detect of installation would result in
full labor charges to repair...
That will generally scare the average customer
into buying a lock set from you which you will
guarantee with some kind of parts/materials
warranty...
Just because the customer has a lock they
want you to do something with doesn't mean
you have to actually touch it -- do so and without
specifically excluding it from coverage, you are
the last trades person to work on it and under
an obligation to repair it if it fails unless you
specifically notify your customer differently
in writing...