If it is the same database system, you may as well use a SERIAL or similar synchronized datatype. The point of using UUIDs is that any participant in a distributed system should be able to generate them, without having to rely on a centralized authority. If the use is purely local then UUIDs would be pointless.
If you have 74 bits of entropy, the birthday paradox says that after 2^37 keys you will hit a 50% risk of a key collision. Whether that is going to be a problem depends on the use case, and on the quality of your RNG.
