I got the McDonalds info from McDonalds.com they have a company history from 1948 to 2000. The happy meal was introduced in 1979, a year before Birdie (the most dispised McD's mascot) was introduced. The years are for US release, but I think Canada was the same. From info I get from
www.m-100.org the 600 would have been priced over $25k in the 60s, maybe more by 1970 depending on the version and degree of customization.