I have an original Linderg 'La Flore' kit that was already open when i bought it and the plastic is fine as far as I can tell.
As a matter of fact, if I swapped out parts on some of my newer Jolly Roger kits, most people wouldn't be able to tell the difference. The molding is crisper of course and some of the spar miss-alignment isn't there, so it is a nicer kit because the molds were still new when it was made.
I can't comment on the name badge on the stern due to the unfortunate fact that it was missing when I got the kit.
You do, however, get the 'La Flore' name badge for the stand which is a dead give away of an original kit, no 'Jolly Roger' or 'Flying Dutchman' name badges to be found.
Adrian