Yes, apparently they did use seperate serial number ranges for each model. Here are some models, years and numbers of mine:
M1903 6.5x54 - 1936 - # 23979 // M 1910 9.5x57 - 1937 - # 11400 // M1924 .30-06 - 1927 - # 299 // M1925 8x60S - 1934 - # 3233 // M1950 7x57 - 1951 - 3092 // Post 1952 Magnum action marked M 1950 6.5x68 - 1957 - 22638. The "military" production runs of M1900s and M1903s(without the bolt hold-down spring) were numbered differently too.
AFAIK the prewar factory ledgers are lost. The Mannlicher Collectors Association www.mannlicher.org has better files of serial numbers than the Steyr factory.