I figure that is a pretty good pull, but with way less overall product being produced I don't figure they are near as hard to pull as the ones from like 20 years ago when if something was serial numbered to 10,000 (like Donruss Elite 1991 and such), it was a MAJOR pull, and most folks were never lucky enough to pull one...I pulled one probably 5 years ago for the first time and I can tell you I opened probably 50 boxes of Donruss 91-95 and I got 1...
now if people buy a box and don't pull a serial numbered card the box sucked, and cards /400 are 'easy' pulls...heck, pulling an old school serial numbered is like pulling a 1/1 these days...alright, maybe not that hard since I haven't pulled a 1/1 in the past 9 years, but close
still an awesome pull, just my commentary on how the hobby has completely changed during my time collecting