How does the garage know the seals are gone? As the turbo seals are not 100% tight so oil will still seep through them, also using thinner oils will cause more penetration through the seal, which can cause a small amount ouf oil to build up by the IC which is natural. Best way to see if turbo is really gone is by monitoring your engine oil, as oil consumption will be high.
The seals can easily be replaced regardless in what state they are in, but when you get a rebuild done they do multiple things to the turbo and not just the seals.