Golden Temple Mail is still called Frontier Mail by many people - though as you say, they may belong to an earlier generation!
But as IRI caters to people across generations, its not a bad idea to include the old name in the train page. If not in title, maybe add a line to the 'Inaugural run' section - "Inaugurated on Wed Sep 05, 1928 as Frontier Mail". What say, #Moderator
Swarna Mandir Mail is simply a translation of its new name.
On the same lines, Paschim Express is referred to as Deluxe by many old-timers and CSTM-CAPE as Jayanthi Janata.