In that case then, my suggestion is to try the games you like.
The ones it can handle, play those, the only way you'll know for sure what you have. And if you got it for $300 & it's capable of playing some of your favorite games, it's a steal.
On the other hand, some of those Best Buy salespersons aren't as dumb as they may make out, although turnover is high due to their sales force not meeting 'quotas'. Not only do they have to sell computers, also a fair amount of 3rd party warranties that's no better & often worse than what the OEM provides, and still the consumer may become stuck with a bill, if not challenged.
So there's a 50% chance that you really had an experienced salesperson playing dumb to gain a sale. I have a computer that's less than 4 years old that was purchased from there as New (Open Box), given to me after only 18 months of use, ran it myself for a few months & now it's sitting, has a 3rd gen i7 that was one of the last quad core notebooks produced on a mass scale. Basically another Best Buy offering by Samsung, the MB had to be replaced as soon as Windows 8.1 was released, then had to be returned again over firmware issues, in all, a total of 4 trips to Best Buy, and Samsung reimbursed her $250 for two 'improper' charges that Best Buy imposed.
Plus whoever worked on it at Best Buy prior to the MB & firmware replacement scratched the bottom of the computer up like mad.
My relative gave it to me for setting up her new one, plus wireless network (new router), plus printer install. $1,200 before taxes for 18 months of use was a poor return on investment (ROI), she was simply fed up & wanted it out of her sight.
So I suggest to give the computer a good workout. You can begin here with testing your PC, be sure to disable the AV while benchmark is running (background resources affects the outcome of test), the download is very small for the test, which after completes, will open in your default browser. At that point, you should then re-enable security for your protection.