If I was you I would try it on. Cuffs that "look" right are tight for me. Cuffs that look quite a bit large fit right.
If it is too small I would frog it and start over or I would do something to change the size with the plan of either folding the large section over when worn.
Odds are blocking will not shrink it (but there are some fibers that steaming will shrink).
Depending on the fiber the blocking may be permenent or the sock could revert back to it's knitted shape after washing.
I only steam block except for reshaping after washing.
Standard Red Heart type acrylics seem to take a permanent block that only reblocking with more steam will change. You may be able to pin that smaller and get it to hold the smaller shape. But it probably wouldn't have much body at the smaller shape and by blocking the ribbing you would "kill" the normal body the ribbing would have at its knitted size.
Wool seems to take the steam blocking well but when washed goes right back to what it was. So the blocking will help even out the stitches but won't permanently change the shape.
I've had an acrylic/nylon blend that shrunk from steam. Steaming and stretching does not seem to undo the shrinkage.