Are assets with Non-manifold geometry safe to use?

Purchased a few models and like most, there is always something to fix.One of the meshes is a low poly crate( like 1700 tris) but made from separate meshes wooden planks.Checking the model from close, maya says that there are some non manifold geometry that it needs to get fixed.I know how to do it and if done, it completely messes other parts of the model(open edges).Simply it was constructed in a pathetic way.I can fix it by hand but so many broken planks after the fix non manifold geometry command…it is just not worth the time and effort.

If i don’t run the fix non manifold geometry option and just import in to udk,model seems to import and work ok without visual problems.

Question is, if i leave in udk a asset that has a non manifold geometry problem, will it corrupt something when later cooking or come back to bite me in some form?