Why? Is your stock inline filter broken in your gas tank? Adding a second inline filter wont filter out anything more and will just add more restrictions to the flow of gas. When you replace the OEM petcock which is part of normal periodic maintenance you get a brand new filter attached (built in) Win Win. You gotta do it anyway and you only need one filter.
The base of the OEM petcock filter has been known to go kidney shaped allowing unfiltered fuel to the carbs.
I've run a NAPA 3006 or equivalent for over 10 years without issue.