Thank You Very Much!
Damien,
Seeing the pictures, what I notice from them is that the bag on this is not original, and neither is the decal on the front of it, and nor is the Adjust-O-Rite plug (the original red one was replaced by a dark blue one).
Originally, since the model 608 is a "Heavy Duty Commercial" model, its bag (same dark blue color) would have read "Royal" (5x) with the crown logo and duty rating ("COMMERCIAL") amid red squares (top and bottom respectively).
The decal on the front of the machine (below the Adjust-O-Rite plug) originally had the Royal marquee (silver logos on black), with "HEAVY DUTY COMMERCIAL" below that (black on silver).
I take it this machine has a 5.4 amp motor given the mfg. date of March 1987 that you confirmed to me when I had months earlier asked you about it.
~Ben