I have a theory to go with your concept
-LN000-012 could be the base loan number. Although looking at my investments I cant work out how the numbering works. As I have two different loans with LN000-017-xxx and the grades and terms are different.
-586 is the investors portion which ended with the loan after purchase at 58.6% filled.
I invested in current loan which is online and got an investor portion of LNxxx-xxx-941. Using my theory that would put loan at 94.1% taken which happened to match the dashboard info for said loan after i bought. The loan had 573 chunks of $50 taken which calculates to 94.08% or 94.1% to 1 decimal place which also matches.
I will see if this holds true for my next buy too as this might just be a coincidence too. I hope that made sense.