It is hard to predict the exact amount of flesh color. Some of that is environmental, and lots of factors including available nutrients, ph, and amount of water can impact that.
Here is a picture as an illustration. The variety is Papa Chonca, and I have tubers (all clones of the same potato) grown in 3 locations. On the left is grown in a bin that high has compost, in the middle was grown in a field that is very sandy, and on the right is from a plant grown in soil with high clay content. The ones grown in the sandy soil had all the protruding growths all over them.
https://scontent-iad3-1.xx.fbcdn.net...19&oe=57653F2E
However, if you bought Adirondack Blue, that is probably not the same as what you purchased many years ago. Adirondack Blue is a 2003 release.
A few others it might have been are All Blue (aka Congo,
Black Russian, Russian Blue, Davis Purple, Eureka Purple, Fenton Blue, Purple Marker, Purple Mountain, Shaw #7, and Blue of Sweden (PSR: KA-67)), or if it was a fingerling, possibly Purple Peruvian. I would put my money on All Blue just based on what was commercially available at that time.
For pictures of quite a few unusual ones or heirlooms, this site has quite a few.
http://www.curzio.com/N/PotatoCatalog.htm