Many years ago when I bought my import 123 blocks (I bought 4 for around $15 a pair) I checked them all for size, squareness, and parallelism. They were all within 0.0002" which was good enough for me
. Not saying they're ALL like that, but it was pretty surprising. Now the finish, deburring, and overall usefulness of them (the tapped hole arrangements are next to useless IMO) wasn't the greatest, but dimensionally they were great. Whether they're still like that or not, I don't know. I have a bunch of other mixed sizes of hardened and ground setup blocks I bought from an old toolmaker that I find more useful so my 123 blocks get used in abusive ways.....
My angle blocks from lee valley were the same. Pleasantly surprised at the accuracy.