Model 600 .308 DOM and replacement parts help

[SilentScope]

Been trying to figure out the date on my Grandpa's model 600. Left side of the barrel appears to be 5 AL 58. Left side of receiver 8174. It need's some TLC as it was his daily driver for deer years ago. Should I replace the trigger guard plate? It has the usual sag. OEM or metal replacement? Also any recommendations for recoil pad? They say the .308 kicks like a mule. What all needs updated on this or checked out to make sure it's still safe to fire? Any upgrades? I've wanted to shoot this rifle for over 30 years. Since I inherited my family's gun collection after my uncles passing my goal is to hunt with and successfully harvest whitetail deer with all my family's personal meat sticks. Thanks everyone

[600RemGuy]

First year, March 1964 for a build date. The internal mag box is installed incorrectly causing the major warp in the trigger guard. It has had the trigger recall-the V on the trigger tells us that. You can still find trigger guards that aren't too warped. The rib is a bit tougher. You mite want to go metal for both warped pieces as is would add some recoil absorbing weight, albeit very little. Do NOT cut the stock for a recoil pad-ruins the value. Make sure the trigger workings stay clean and dry-no oils-dry lubes only. Watch that fluids from the barrel don't seep down into the trigger.