Is it possible to check Steam code PC game (Elder Scrolls Anthology) without activating it?

I think I got scammed which caused by my zero knowledge of PC games. I bought this used PC game Elder Scrolls Anthology at the yard sale. I hardly play PC games, and I don't know much about how Steam works. I bought this for my nephew since he plays some PC games and I have to buy something for his birthday soon. There are 5 games and the guy said, he only played SKYRIM (last and latest one) and he said he only used a code just for that. He also showed ebay listings and it seemed that $20 was a quiet good price, well, for a birthday gift. I came back home and left it on desk for a week. Today, I checked the code in the package, and turns out there's only one code. There are NO other 4 codes for 4 other games. It seems that this one code does for all 5 games. Yeah, the money down drain. I know, what a sap. I also checked the discs of other games they all have some minor scratches. That was the story of my walk of shame. Anyway, I'm pretty sure this guy used this code, but just for the precaution, I just want to check if it's activated or not in case I can still give it to my nephew. Could someone shed some lights on this situation with some information of this boxset?