Tint question

I got my windows tinted and a spray in liner this past Tuesday. The place was more of a liner shop than a tint shop. Originally they quoted $970 for ceramic tint and the liner. But when I went to pay they charged $870. I didn't really think anything of it, maybe they thought I had the longer bed or included the rails, I have plastic rail covers. Last night I was looking at my receipt and they charged me for regular tint. When I was paying it wasn't in the computer. It was the owner checking me out. At first it was coming up even less. When he asked me what I had done he forgot the toolbox. I just said tint, bedliner with the tool box. I wasn't trying to rip him off I didn't think to say ceramic tint. My question is, is there anyway to tell if it is ceramic now that it is installed? I was thinking about getting a heatlamp bulb to compare it to my other two cars. One is definitely metallic and the other is definitely ceramic tint. Sorry for the long post thanks in advance

edit to add I don't mind coming off the extra $100 for the warranty protection

edit they also have great reviews and seem pretty honest. But I would like to be sure I got/get what I pay for

 

I would just call and ask tbh, I highly doubt they would make you pay the difference since it was their mistake on the invoice. They can just ask the person who installed it.