You will have to call Ruger.
It is the serial number. Ruger's web site has sn data on it.
You will have to call Ruger for the age; 100-400
1979-1981
Go to the Ruger Website. Under customer service, select historical data, the type of gun, the model, and check the table for serial number range data.
No. Your Mini-14 is a 183 series. The first three numbers in the serial number, followed by a dash, are the series code. Ruger made changes to the Mini-14 with the introduction of the 181 series. Many 180 series Mini-14 parts do not interchange with 181 and later series parts.
Call Ruger and they will tell you.
The serial number seems to indicate it was manufactured in 1989. It's a regular Mini-14 - not a Ranch model. If you want more specifics about your rifle, you can contact Ruger at 603-865-2424. You'll be asked to leave a message. In that message, leave the type of rifle, serial number, and a contact number for them to reach you. In a week to ten days, you'll receive a call from Ruger, where all your questions about your specific rifle may be answered.
The Ruger website, under Customer Service, has a downloadable owners manual for your Mini 14.
You can contact Ruger's customer service to find out.
If you go to Ruger's website you can download the manual for your mini 14 for free. It tells how to disassemble your gun in the manual.
For Date of Manufacture, go to the Ruger website. Under Customer service, select historical data, then rifle, then your model- and the years of production by serial number are listed. Value will be based on condition- about $400-500.