Let's make this easy. Go to
www.biggerhammer.net and go to the Manuals section. Look for the M14 manual FM 23-8. Download that free government manual to your C: drive. That will give you what you want to know regarding disassembly and parts identification.
On scope mounts, IMHO, a steel construction three point scope mount is the way to go. You need three points of contact to keep the scope from shifting. The SA, Inc. Third Generation scope mount is an aluminum two point mount. Three points of contact makes the mount much more rock solid. Brookfield Precision Tool proved this in the XM25. It's more money but go with steel construction. Aluminum heats up faster than the receiver does. That means it's going to expand and contract at different rates than the receiver. If you are taking one shot to hit a deer then it works. If you are looking at reptilian alien defense, the steel construction mount is needed. IMHO,
www.smithenterprise.com or
www.sadlak.com are the M14 scope mounts I recommend without hesitation.
You need to know that commercial M14 rifle receiver geometry is not always in accordance with the USGI receiver drawing 7790189. Therefore, some M14 scope mounts don't fit perfectly. Please read the free online M14 Scope Mount FAQ on my web site
www.imageseek.com/m1a. It will save you some heartache. The ARMS #18 mount is a great mount but because it sits so low SOME folks have cases get stuck OCCASIONALLY in the action. That 's not critical if you are using it for target shooting or blasting coyotes. HTH