is my car in any way special/rare or more valuable than any other? 70 340.

There is a web site that you can register your VIN # on.
Your VIN # indicates that it was built in Windsor with the "R" signifying that.
If you have the fender tag it would state as to whether it was built for export with a code of "Y05" for export to USA or " Y07" for Canada.
This info can be validated by going on the web and it will decode the fender tag.
On this Dart Registry website Joel Cooper who manages it told me the following:
Total 1970 340 Darts made-13,785
Total for USA export - 10382
3 Speed cars-955
4 Speed cars-4423
Auto trans cars- 5004
On your vin tag it will tell you the trans code and also the color
This may help make your mind up.
The attached photos show my restored # match green 4 speed and a non # match purple 4 speed

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