There was a thread about this the other week!!
Friday the 13th Part 1 is owned by Warner in the UK so the dvd of that is the uncut unrated edition.
Paramount own the rest of the series and even Part 1 in the US.
It was their decision not to release the unrated gory versions but to stick with the R rated cut versions and this affects the US and UK.
They released a boxset in the US which had some gory cut scenes as extra features but not within the film.
I woukld expect that if Paramount want to get people interested in buying the films on Bluray that would be the obvious point in time when they will market the uncut versions.
In the UK the uncut versions would still get 18 but back when the films were made the R rated versions were still too strong for a 15 - which perhaps would be the rating they would get today
