No such Colt model
1978-79.
The gun was made in 1922.
made in 1982
@ 1975
Proofhouse.com has sn tables that you can use.
No known sn data published.
93-94 time frame.
colt .380 mod. 1908 serial #112840 was mfg, between 1933 and 1934. hope this helps. don
Your serial number indicates that your Marlin mod 60 rifle was made in the year 1978.
your trapdoor was made in 1878
Check the Wincester section at Proofhouse.com