Where’s the Remington gurus around here?? Have a question...

I bought a beautiful Rem 700 BDL in .243 today. Nice wood stock, jeweled bolt, iron sights and front site is hooded. The guy I got it from said it’s a 70’s model.
I know you can look at the barrel code to get approximate year of manufacture, but this gun doesn’t have any letters for that. All it has there is “64.”

I can’t call Remington (closed) to get that info so is there any other way to find out when my gun was made??

Picture is attached

https://photos.app.goo.gl/YPX8PVJDaDyTKpqN9