@Biggfred- yes they are common in that respect. This particular dealer is one of the largest on the East Coast, so his inventory levels are high on many on the standard items. If I wanted to go through Morgans (and if he would have let me) I could have spent a week or two just looking at them. The thing about Ikes is not that they are rare in and of themselves- it's that getting one about MS-63 is an uncommon occurance. The 71-S Blue Pack Ikes were not treated with any care at all when the mint and treasury made them and put them out. I'd say the typical condition ranged from MS-50 to MS-63 (yes, I coined the term MS-50).
The fact is, I went in expecting to drop about $150 on blue packs and walked away with only three. That should tell you how nasty they tend to be. Another thing to keep in mind is just how these blue packs find their way back to dealers after a period of forty years. Many of these were sold back to this dealer by collectors and non-collectors who picked these up along the way and grew tired of them.
I would have recommended that 50% of these be melted for bullion if I thought it was my place. There are fewer 1971-S Ikes in grades above MS-66 than there are chain cents in existence.