What is this brass item?

What is this brass D&RG. RR plate from? I was at a model railroad and toy show in Medina, Ohio yesterday and bought this. It measures 5 3/4" in diameter, is solid brass and is painted red and black. An old guy much older than me and i'm 63 had it on his table. i asked him what is it? He said he got it off a RR engineer over 30 years ago and wasn't exactly sure what it was. On the REA tag attached to it with wire on the back is written locomotive plate. I presume this is most likely some fantasy brass RR plate. It has 3 drilled countersunk mounting holes for screws wich the top hole is not in line with the top point of the red star wich seemed to be a bit off to me. I have never seen a small D&RG. RR plate like this before. If it is some fantasy fake plate i'm not out to much as i only paid $30 for it. Was just curious what it is? I figured some of you guy's on here would know what it is. Thank you!