How to display the numerical values of the Magnitude Frequency Response Guidelines?

When Frequency Response/Spectrum is selected as the active plot type, guidelines can be added. Go to Plot->Plot Type Settings->Frequency Response/Spectrum…. Then click the guidelines  button to open the dialog shown below.

The numerical values are displayed if  is checked as shown to the left in the figure below.

To display the numerical value of these lines can also be done in the legend as shown below

To do this, go to Plot-> Layout->Edit... and click the Legend tab. In the Legend Style list box choose Last Values as shown below.

This means that the last value of the series will be displayed in the legend and not the curve name. Since the guidelines are straight lines this is the value of the guideline.