A part like LM323K is one to be highly suspicious of. Power transistors and Voltage regulators are not something to buy from China (or Jameco as far as I'm concerned) as the clones are greatly underspec'd. They will work if you don't run them anywhere near the limits, but if you drive them hard, poof.
With a precise scale you can usually weigh a transistor or v-reg against a known real one and tell is a fake clone. The silicon / whatever inside of them is heavier on real parts.
I had a box used as repackaging come in recently. I noticed the box was a FAKE STMicro packaging for 7805V. It had Engrish and an upside down logo on it just like the Clone M2732As come in. This stuff is winding up in the hands of domestic resellers. People reselling parts should pay close attention.
For voltage regulators its time to come up with good switching buck regulator retrofits. I have a 5v power supplies running off of LM2679T-5.0. They are like $5 each but run really cool/efficient and play nice in pinball boards as long as you wire it up right.