Depending on your PDF software, you CAN see the fonts being used in the final render.
File > Document Properties > Fonts
Adobe:
In this example, the report is being generated using Courier, Courier-Bold, and also FrutigerLTStd-Bold & LIght.
Those latter fonts, you can see are labels as “embedded”.
I would assume if you checked this on your report, you’ll see Helvetica listed as that is the default substitute for Arial fonts.