If you only sent in your photocopy, they'll need to verify it against the original copy and that can delay your process. Hence, it is highly advised to send in your original copy. They keep it at the embassy and send it back alongside your renewed license.

On a related note, I just realized that they charge $150 for Nepalese passport. Compared to a US one that costs $135 for first-time applicants and $110 for a renewal, it is daylight robbery.