There seems to be different dates floating around on the internet. The mountie first appeared in the 1953 Marlin catalog*, though I find info that states 1954 was the first year of production (wiki). Some info I had read said the Mountie was made until 1983 (wiki), while other info said 87 or 88 (shootersforum). Wiki claims that it was known variously as 39A Mountie, 39M Mountie and 1897 Mountie.
From shootersforum.com:
Model 39 1922 - 1939
Model 39A 1st variation 1939 - 1940
Model 39A 2nd variation 1940 - 1941
Model 39A 3rd variation 1941 - 1945
Model 39A 4th variation 1945 - 1951
Model 39A 5th variation 1951 - 1953
Golden 39A 1960 - 1987
Model 39A " Mountie" 1953 -1972
90th Anniversary 39A 1961
90th Anniversary 39A "Mountie Carbine" 1960
Model 39A-DL 1960 -1963
Model 39A Octagon 1973
Model 39 Carbine 1963 - 1967
Model 39D 1971 - 1973
Model 39AS 1988
Model 39TDS 1988 - 1995
Model 39M Discontinued 1987
Model 39M Octagon 1973
Model 39 Century LTD 1970
Model 39A Article-2 1971
Model 39M Article-2 Carbine (date unknown)
*Marlin Firearms: A History... by William Brophy
G&A Article