On U.K. cars the seal was changed (at least part number-wise) in 04/92 (a bit later in Japan). There is no guarantee that the part was modified for improved sealing and, as far as I can briefly ascertain, no technical bulletin is available. Did this known problem come to light during the production run of the U.K. cars? Probably not.
All weatherstrips ordered now would be supplied to the new pattern as the old part numbers supercede to it. I've never had the two side by side to make a comparison, but if a Series 1 owner and a Series 2 owner were to find themselves side by side at a meeting, a comparison would be useful!