1969-70 would be a 10-5, my 6" 10-5 is a 1974 production.
Model 10's are great guns, and they tend to multiply.....I've got M&P's-M10's from the 40's right on up to my 10-14 made in 2003, and everywhere in between. Old and new, I love 'em all......some people like fancy, pretty guns, I like Model 10's, just a meat and potatoes working gun, with lots of style.