ANy difference between 5.X ports tree and 4.X ports tree ?

[Pete French]

As I understand it, the ports tree is the same for both STABLE and
CURRENT isnt it ? So can I safely do a cvsup with the line

ports-all tag=RELEASE_5_2_0

to update my ports collection to the set which comes with 5.2
release, despite the fact I am running 4.9 ? I want to do this
as I know the sets of ports which are marked for a RELEASE are
tested to all work together, which saves some of the problems I sometimes
get cvsupping at an arbitrary time.

The only reason I ask is that I ran the above command and it looked like
it altered almost every port in the tree!

-pcf.