I think that 69 was the last year for body color wheels. All three of my 70 Darts came with semi-gloss black wheels with full wheel covers, including the one my Dad bought new, and an 'old lady car I got with 27,000 original miles.
it changed later then 70 ( i want to say 72 or 73) but i don't remember. it has been posted here before.. up to at least 70 if you got full wheel covers you got black wheels. if you got dog dished you got body color wheels.