No, the pin is for the bolt lock and is on all shrouds. Both sides have the same addition of metal for the "tits". Since there is more metal on these than the standard shrouds, it appears that Sedgley may have made their own shrouds. When they got to the speed ignition there is more metal internally than the std and couldn't really have been a welded addition, so that adds to the theory that they made their own shrouds. Mike has what I believe is the reason for the "tits".
Dan