I'm almost 100% certain that the wood floor tiles, the obelisks, and the red carpet are in RMVX's run time package, I've used it plenty of times, and those exact tiles are right in there, but hey, if you're sure you got them from a reliable free source, more power to you. Like I said, I wasn't trying to be a buzzkill or be rude about it in any way, I'm actually really impressed that you put together a full RPG with GM:S, I just hope you don't run into any stupid legal problems because of something like a tileset. Best of luck with this and your future endeavors man!
I can definitely see why you got that confused. The creator(s?) of the tileset got a lot of inspiration from the run time package, but if you take a look at them side by side then you can see that they are different. There are actually some things in the run time that I wish First Seed Material had made a version.
I've got a copy of the run time downloaded on my computer and I'll admit, the red carpet is extremely similar in style, but there are some differences. Anyways thanks anyways. I certainly wouldn't want to get into any trouble.