If you looking into plinking shoot the bullets and primer. Primers really don't have a shelf life I don't think, but materials have changed some in the last 40 years. Not sure about the last 20.

Good place to buys stuff.

www.midwayusa.com
www.grafs.com
www.cabelas.com
I love all three.

I use Varget and IMR4064 for my 308Win loads. Never used 4350. Sounds a little slow to me. With a 165gr bullet, 47 to 48gr of Varget is what most people use.

I am into reloading for the accuracy. So I don't skimp on much. If it was me I would buy modern bullets, and primers. Brass won't matter much.