Making UUIDs out of LSB/MSB

So, our operational DB has a table where we store bill images. The table that stores the images has columns for least- and most-important-bits. The database has a function called UUID which takes those two values (bill_lsb and bill_msb) and outputs a unique ID. My question… is there any way I can use dbt to cast the two bits columns as the UUID’s that they’re meant to represent? That way the UUID’s can just live in the downstream tables on their own, in their own column? I’ve searched around for macros and dbt utils but I’m not seeing what I think I’m looking for. Then again, I’m not sure I would know what I need. Does this ask make sense? Thank you ahead of time!