Researching R700 for .30-06 Build

[DRAGON64]

In looking for a suitable action for a .30-06 build, and I keep running into threads where posters are asking about serial number prefix's and digits of certain vintage actions etc. What is it with the older actions that people ask about certain serial numbers or ranges? I did see where an inquiry was made into an R700 thread, about a rifle made in 1966; the poster thought that the action could be viable candidate for an M40 clone... (maybe I just answered my own question)

What are the most sought after R700 actions?

 

[MG-70]

To add to the question, if I may. I've also wandered why people advertise a rifle or receiver as G prefix, etc., and assumed it was to specify that it was built during Dupont's involvement with the company, when quality was supposedly better.

 

[irondude]

Build Date - Remington 700 Actions?

 

[MG-70]

Build Date - Remington 700 Actions?

Much obliged!