I don't know what the "-MIL" means on the part number for that part (it certainly isn't for "military") but I have seen lots of complaints for parts that are marked with this. Seems that this is yet another chinese wonderbatch infiltrating ebay.

The EZSBC is a good solution to this problem but if you got it working, leave it be. Also, the LM323K regulators are not yet obsolete and are still listed on their "active" list of components. You can buy brand new ones from the manufacturer at $37 each with a 1000 piece min buy (yeow!). "Bargain" price of $65 each from Mouser. Yeah, go to EZSBC if you need to replace.

Also, let your source for these know that these parts are questionable. Give them heads up so they can change their source.