Frank, did you happen to come across this black Chevelle at the Norwood Motors dealership or on the streets of Rhode Island?
This Chevelle was originally assembled at the Framingham plant as an L89 (a couple of months after yours, in May of 1969) and was converted at Norwood Motors to an L88 (along with this noticeable wheel/tire combination and other mod's) before the original owner drove it off the lot on June 21, 1969.
Also... did your Burnished Brown Chevelle leave the dealership with the factory wheels or ???