Full disclosure, 7140 is 'on trial' with 188 and 7602 from Inchicore to Ballybrophy before entering service but is specially captioned as" the last of the first batch" and "the finished article" by the author Michael McMahon.
All that said, it is hard to find examples of Mk3 with any colors showing on the bogies in service (if anyone has some, please post). Likewise if you look at the NIR Mk2 stock in the 1970s the known colored details are substantially muted in color within a few months of entering service
When IRM first did their models I have to say that I like seeing the CADs highlighting with different colors the component feature of the wagons, sadly all gone now with no end user input wanted (or needed I suspect)