Auction buy Stihl 026

Yes, but ZAMA quality control standards are a lot higher than what you get with "XYZ ching ping industries" brand stuff that is common on ebay and amazon.
Chinese manufactures can build to any standard, just like everybody else...can make some pretty decent stuff if your price point is a little higher...just look where your computer, TV, and cell phone was made.

On the bar temp issue...getting boiling hot after cutting one piece of oak lumber is not normal (with a sharp chain)...I would expect to see maybe 125*F when checked with a infrared thermometer...150*F max.
To me, 150*F would be more expected after cutting long enough to have went through a tank of fuel...I sharpen my chains by hand after every couple tanks of fuel and have no problem advancing the chain on the bar with bare fingers...and speaking of sliding the chain on the bar. When the chain is properly tightened, does it slide smoothly across the bar (by hand) with no "notchy-ness"? If it does, I expect that the chain and the drive sprocket are a match. That's a good way to check for a mismatched chain and sprocket as far as wear too...new chain on an old worn sprocket will not slide smoothly, it will be kinda herky jerky...same with a new sprocket with and old worn ("stretched") chain...the chain and sprocket have to at least halfway "match" as far as wear. Mismatch can actually cause chain breakage.