What year is your model 60? Take the first 2 digits of the serial number and subtract from 100 and you have year. Example s/n 26xxxxxx = 1974, s/n 15xxxxx = 1985, s/n 02xxxxxx = 1998 and s/n 98xxxxxx = 2002.
I am aware of 3 different style model 60 stocks, old trigger guard style, new trigger guard style and new trigger guard style with last shot hold open.
Give us more information of what you have and the stocks you are looking at.