the fact that it is the "same" game does not mean its the "same" game...
er... that didn't make sense at all
if the versions where released at different times, one could be more updated out of the box (that happened to the russian version of STALKER, the american version has more stuff even tho both are the "same" game out of the box.)
the facts being:
you should download the patch that was made for your version. (both d2d/dvd wise and europe/america wise)