According to the Datsun Model Guides, US weights are:

(manual trans)
2-dr Sedan 1630 lbs
2-dr Coupe 1650 lbs

(auto trans)
2-dr Sedan 1705 lbs
2-dr Coupe 1725 lbs

depending on which model year you look at, the weights will be different.
I can't remember what the sedan weighed for the 1971 model year, but I do know that the coupe weighed 1609 lbs.for 1971.
this is due to different emision and safty requirements for each respective model year.
this debate has taken place before, check the archives. as was decided in the past, the sedan is slightly lighter than the coupe, and it will always be so.

It seems a bit obvious doesn't it? With the extra glass the coupe couldn't help but be heavier.
Coupe doesn't mean sport!

My Datsun Tech Manual for 1972 list dry weight for the 2-door sedan as 1499 pounds and the Deluxe model as 1535 pounds. The coupe dry weight is listed ad 1575.

I have never seen a sedan that was not the Deluxe model. I assume that the 4-door weighs more.

Mareo

Do all deluxe models have the deluxe badge? Mine doesn't have any mention of deluxe on it, what were the differences?

As with Mareo, I too never have never seen a US model sedan (2-dr) that wasn't a "Deluxe". The funny thing is ... the Deluxe models had no carpet, no radio, plain black seats. At least in the US.

I always wondered if it meant it had disk brakes instead of drums, although I've never seen a drum brake model here.

In Japan, there were the GL and GX
In Portugal the famous S1
In New Zealand the SSS

My 72 Deluxe had an AM radio. I have always assumes that the Deluxe had the larger 20 mm sway bar, cushier seats, disc brakes, radio and softer shocks but I have never seen a list. Maybe someday, someone will come up with some lost Nissan doument explaining it all.

I think the weight listing the 1200 in the 1600 pound range may be wet weight with gas, water, oil and spare tire.

Mareo

The radio was listed as a dealer-installed option in the brochure at http://www.ratdat.com/brochuregal/b110brgal/image7.htm
All the Deluxe Sedans I've seen had a radio block-off plate. My Sedan did have the larger sway bar though.

The brochure also lists weights as:
2-dr Sedan 1587 lbs
2-dr Coupe 1609 lbs
Some of these figures are probably "curb weight" (typically with all fluids and 1/2 tank of fuel) and some may be "dry weight". Or it could just be the options of the vehicle the sales people chose to weigh, or it could be a pre-production estimate in one, and an actual weight figure in another ... when I weighed my near-stock 2-dr sedan at the scales, it was around 1640 lbs. I don't recall how full the tank was at the time.

One 1200 that I have seen may have been the 'standard' model it had non reclining buckets. Or was that just a feature on the earlier models? What type of dash does the 2 door sedan have? Is it the round binnacle one or the flat one?