When the time came to change the fresh water drain valve on my previous 87 AS I just unscrewed the 2 screws holding the valve in place, wiggled out the old valve, and pushed the new one in place and used 2 new screws.
It only took a few minutes to actually change it out. It never leaked or caused a problem for the last 15 years that I owned that trailer after that point in time.
Granted, I don't know if there is something different with the new trailers but the valve on my 2010 looks like the same one they used back in 87.
Maybe I was just lucky, or maybe that is all that is needed to change one out.
Take my advise with a grain of salt whenever possible.