Unlikely unless there are other known high-value stamps in the collection. You'll need to check the watermark to see if it is a 519 - will need to be a double line watermark. You can check yourself with some lighter fluid and a black dish, but if you don't have a lot of experience, you may not be able to tell definitively. . .I suggest you take it to a stamp club, show, or dealer and they can tell you pretty quickly. If you have interest in collecting, check this site to learn how to check for watermarks: http://www.stampsmarter.com/learnin...termark.html
You'll also need to double check the perforations, but the double line watermark is the distinguishing feature on a 519.