Yu Sui Sheng 喻遂生 writes in his Collected Research Essays on the Naxi Dongba Script (纳西东巴文研究丛稿) about the recording of dates on historical land contracts.
For pre-Republican Chinese dates, the Naxi use the word 
kha21 ga33, meaning ‘monarch’ or ‘dynasty’ as the imperial-reign prefix . Yu notes that the kha21, depicted as phonetic loan character ‘bitter’ can sometimes be replaced with the character 
a33 (this seems to be a non standard variant, the pronunciation remains kha21).
In the 30th year of the reign of Emperor Guangxu, Chinese 光绪三十年, would be:
kha21 ga33 / kua33 sy55 / si33 / tsher21 / khv55
Word for word that’s :
emperor / Guangxu / three / ten / year.
(Here the Chinese Guangxu 光绪 is transcribed phonetically in Naxi as kua33 sy55).
Interesting that in Yu’s examples, year (khv55) is depicted with the character for reap or harvest, 
whereas in the scriptures year is more traditionally written as 
.
The Republican Period, Chinese minguo 民国, is phonetically transcribed in Naxi as 
mi21 kue24.