You will have to call Taurus to find out.
the year is 1968
Taurus makes pretty decent revolvers, and they're reliable.
Your serial number indicates that your Marlin mod 60 rifle was made in the year 1978.
It should be the last 4 digits of the serial number. That will give you the year.
By the first two digits of the serial number. AB
Depending on condition, about $250-$300.
Where can you locate a parts breakdown and availability for a Sears mod. 42-103-2840-22 caliber rifle?
Best left to a gunsmith
$100 to $125
Started in 1983
See related link
No it is a custom built map