dhunter
My DS I ID plate is 13742 and sail # 2383. I am pretty sure that this is an accurate set of numbers. I am also reasonable certain that my DS I is a 1968.
Yours seems to be a very nice DS I and with a number of modifications, like many of us have with the older DS I's. It looks like the through deck fittings around mast were added to manage the spinnaker pole down haul and foreguy. The ones in the back are certainly for the spinnaker sheets and are similar to the ones added to my DS I. I am not sure what the function of the one an the bow is. My guess is to adjust the height of the jib tack.
A traveler was also added as this is certainly not standard. The location of the job sheet blocks is also interestingas they are quite far forward on the bow. Normally they are on the inside of the cockpit coming.
I assume they have been moved from this inside standard placement on the cockpit comings. In addition your mast and boom seem to a Proctor.
So my guess is that the previous owner set this DS I up for racing. Note also the missing floorboards which would indicate that the owner sailed her 'light'.
So all in all this is a very nice DS I and you will have to decide if you want to leave her the way she is or go back to a more traditional set up.
Have fun!