No, not as individual part for a reasonable price.
I found lots of defective WC6515 on the market, but shipping them seems to be impossible. I'm betting each one of them has a working ADF scan module...
The part number of the scan module seems to be custom, officially liteon has not documented anything starting with "DL620", it should be "DL520":
Since my device works fine with the (repaired) flatbed scanner, I've got lots of time to find a solution.
FYI: I finally found someone who would ship their defective unit to me.
The unit also had the 062-380 error, and it seems like the flatbed scan module was at fault. Since I had already restored my unit to partial function by swapping flatbed / DADF scanner module, it was a <15 minutes fix to swap in the DADF module from the "bought for parts" unit.
I now have a fully working unit again and an additional set of drums, toner and waste toner bottle.
Total cost including shipping was less than an complete (original) toner set :-)