The values of bg_1 and bg_2 seem incorrect in the-values.md.
For example, comparing the values in the-values.md and urxvt/selenized-dark.xdefaults, you can see differences like:

Dark:
bg_1: #184956 vs. #174956
bg_2: #2d5b69 vs. #325b66

Light:
bg_1: #ece3cc vs. #e9e4d0
bg_2: #d5cdb6 vs. #cfcebe

After having a look at the git history, I found that the document shows an older version of color set. Commit c5d9447 seems to be related.