Give it the once over if it is well used. Check these as a preliminary.
(1). Bar condition. Take the chain off and see if the bar has a lip coming off of the rails. This would indicate it has been well used indeed. It needs to be dressed by removing the burr with a file so that the surface is filed to a 90 degree at the edge, a small chamfer is ok on the corner.
(2). Check the condition of your chain. If not familiar with sharpening there are many threads here and some stuff at stihl.com. Otherwise it's a good $5.00 investment to have it professionally sharpened. This way when you really test it for the first time you'll know the feel of a sharp chain.
(3). Check the air filter for cleanness, it could save your piston and cylinder. If the carb injests a certain amount of saw dust it can score the piston and cylinder. Check your fuel filter as well, for $5.00 you can usually replace it. If you use the saw regularly I would replace it every year.
(4). Use premium gas, not the low-octane stuff, and genuine Stihl HP mix oil. With the problem of ethanol now days some are even going to aviation fuel. Ethanol is DEFINITELY a problem for 2 cycle equipment.
(5). Bar chain oil. Most of these saws that come through here have burnt motor oil in the bar chain oil reservoir. Though it is cheap, it is not good for your bar, oil filter pickup and the life of your chain. If not sure, drain it out, and start with a good bar chain oil. The bar chain oil has ingredients that make it adhere to the chain and provide adequate lube for your bar rails and chain. (Tractor Supply had theirs on sale for $6.00 a gallon.)
If it is indeed running and running well, give it the once over and put it in some wood. These are nice saws, I've repaired, ran and sold a crock load of them. If cared for you should be reasonably happy.
Happy Sawing.