Unless someone here knows specifically- you can consider numbers and names on large production cues from years ago to represent lot numbers, order numbers, individual rooms or companies that the cues were made for distribution, etc. etc. Brunswick cues for many years had all sorts of numbers on them. if the Dufferin has a maple leaf in a glass window it is not one of their oldest cues. The original production cues did not have a maple leaf- I know, I own one - there was a CD- Canadian Dufferin- initials on the cue back then.
I would guess that Saxon was a cue distributor/wholesaler of sorts and that the ds-1300 was a lot number for that distribution.