Your serial number indicates that your Marlin model 782 was made in the year 1977.
Seems to be a descrepency here. There were no model 36 marlins made with Microgoove barrels. The model 336 was made with a Microgroove barrel, and if that's what you have then your's was made in 1972.
the year is 1977
53 years old.
Check the receiver and barrel.
Check the barrel and receiver.
Check the frame and barrel.
Look on the barrel and receiver.
how much does it cost a 1983 marlin 38-55 hex barrel?
To determine the age of a Marlin Model with a Micro Groove Barrel, you can reference the serial number, which typically indicates the year of manufacture. Marlin has specific serial number ranges that correspond to different production years. You can consult a Marlin serial number lookup chart or contact Marlin directly for precise dating based on the serial number. Remember that the model and type of firearm may influence the specific dating process.
85 years
go to: Marlinfirearms.com and pose the question to them
your marlin was made in 1904.