Re: restocking a 721
The 721 was the forerunner of the 700. A few different (more costly) manufacturing steps and features in the 721, but the footprint of the actions are virtually the same. However, the 721 was made back when scopes on rifles were the exception, not the rule, so the drop at the heel of the stock was low enough to sight through the iron sights on the barrel, not higher to get a cheek weld for sighting through a scope.
That's what he means by: "the stock is for iron sights."