Wow, I looked more and found the same thing, actually I think its hit and miss on who has them in stock and who dont.

I got a set of the MS1266HGX in Feb and although I dont recall if it was summit or jegs they had them in stock.

Of course you can find the 318/340 ones now.

Its cool summit is going to cover the cost as most bolt in kits are known not to be bolt in kits.