The "histone code" is not like the genetic code where one codon in an ORF always is translated to a single amino acid. It's closer to something like GC content or CpG islands: a single instance doesn't tell you anything, but enrichment over some finite window may be biologically significant.
You may want to review the basics, starting with the Wikipedia page on the histone code. In particular read the paragraphs at the end:
Every nucleosome in a cell can therefore have a different set of
modifications, raising the question of whether common patterns of
histone modifications exist. A recent study of about 40 histone
modifications across human gene promoters found over 4000 different
combinations used, over 3000 occurring at only a single promoter.
However, patterns were discovered including a set of 17 histone
modifications that are present together at over 3000 genes.
Therefore, patterns of histone modifications do occur but they are
very intricate, and we currently have detailed biochemical
understanding of the importance of a relatively small number of