Noooo.... Harbor Freight sells them for less than $5...
It's just like a doctors stethoscope but without the flat bit on the end...
You just put the end of the tube at different paces and try to find the noise source... (I took the end stick bit off, and just use the chrome tube part.. seems to work better for me)...
... you can also just put your ear to the handle end of a long screwdriver and touch the tip at different places (just can't do corners very well)...
...(cam-chain is on the right side... and the sound is usually in the lower case)......but sound location can be tricky...
Your noise sounds more like valves at upper left of engine... Are they adjusted?...
http://www.harborfreight.com/mechanics-stethoscope-41966.html