Dates, Times and Timezones - How are they incorporated in Interval?
Yes, if not it would cause all kinds of errors.  when doing math on a date for example 1 month ago, it does take the date to be subtract from and figures out what to do from there,  it does not just subtract 30 days. 

links will answer your question
wiki interval
another site

also consider this simple query

select '03-01-2019'::date - interval '30 day',
'03-01-2019'::date -interval '1 month'