There is no definate answer on this one, i beleive they would have been sold with both variants.
We see introduction of the Cal.15 movement in the 1972 catalog
http://www.onthedash.com/Guide/_Catalogs/1972_Brochure_Cal_15/?show=72Cal15P2P3P4.jpg:
where the 1533G is shown with a Mk.I bracelet.
Then we see the first sign of a Mk.II bracelt in the 1974 catalog (albeit on a manual wind 74033 model) http://www.onthedash.com/Guide/_Catalogs/1974_Chronograph_Catalog/?show=23.jpg
The 1533 was still available for sale beyond 1974 , maybe through to 1977 , but we never see mention of the Mk.I bracelet after that 1972 catalog. Logic says that if the buyer wanted a bracelet for their Monaco after 1972 the the Mark.II was the only one available. Read into it what you will - logic , deduction , assumption but i beleive both bracelets are correct for the 1533 series.

Cheers - Darren

Do you guys know if the 1533G Monaco came with the Mk1 or Mk2 NSA
: bracelet originally, or was it available with either?

: -David