Checked Microcat - there is only one part given for the seal (ALR4770) and you have already found it. There are no replacements or alternatives. Can only assume someone put something else in there before.
Sorry can't help any further
Dealer says that part ALR4770 has been superceded by a new design, but has retained the same part number.
Got ALR4770 here, but it doesn't fit the old trim. So, rather than buying just the rubber trim (£7) you now have to buy the newly designed metal trim to fit the newly designed rubber trim, which comes in at around £35!
Using a Stanley knife I've cut off the excess rubber, used a blowtorch to bend the rubber to the same shape as the old and made it fit the old trim.