Currently, there are two separate examples of number lines in the BANA Guidelines for the Transcription of Early Educational Materials from Print to Braille.
On print page 46, there is a sample transcription of a number line for a UEB Math/Science transcription; that number line DOES have numeric indicators.
On print page 80, there is a sample transcription of a number line for a UEB with Nemeth transcription; that number line does NOT include any numeric indicators.
In general, as Guidelines and Standards for Tactile Graphics (GSTG) tells us, the numeric indicator should be omitted when depicting number lines (especially below the number line).
Based on my understanding of coming updates to the GSTG, I think you are fine to not use the numeric indicators. Please let me suggest that 1) you do not use a numeric passage around any number line and 2) you do explain on the Transcriber's Notes page that labels below number lines are transcribed without numeric indicators.