I like reading about the history of dog breeds. It took me awhile but I tracked down one about pugs that has some great info. It turns out that it is believed they developed from the same lines as the bullmastiff and not bulldogs. There are even photos of skulls of various dogs included. It is most interesting to note that when they were developed that they did have a nose on them, and not the extreme flat faces they have now. (or even as shown on the book cover)
I'm throwing in a bunch of Jenny photos for someone to look at that has smooth brussell griffons. It has been mentioned that perhaps she is a cross with a smooth BG due to how much she looks like one in the face and has a similar body type. I have only seen one smooth BG in person and it was such a long time ago I am unsure if this is a realistic possibility. After seeing the photos in the history book however I believe she looks like more of the original pug type. I think they used to call that a throwback.
Another thing I found interesting from the book is that is used to be very common practice to crop pugs ears.