Folks have been busting up mint sets for the better coins for many years. Not much will be found in the 70's sets that are worth having graded. As green said above, buy them already graded and save a lot of money.
I do agree. Even back in 1978 it took a lot of shoe leather to chase down Gems in the mint sets. It's not only easier now but cheaper as well. I think most moderns sell stupid cheap. I'll probably make a few bucks an hour for all the work and time I put into them after deducting expenses. But the sets out there aren't that much worse than they were in 1978 other than all the tarnished coins.
A Canon T3 Rebel which is my fathers and old and his macrolens canon usm 100mm 1:2:8. Otherwise I use my canon G9X Mark II which is the most baddest camera on the market for a point and shoot.