Another Welcome from Ontario, Canada!
Is this the quilt you are referencing?
http://moonshinebymonicapoole.typepa...-blog/2013/07/
Cute Quilt!
Yes, you could just do the centre part of the quilt and add on whatever size of border(s) you wish.
.... and No, there are no hard and fast rules as to how wide your border(s) must be.
As is often said here on the QB ... it's your quilt, and you can make it however you like!
To me, that is the FUN part of quilting ... being able to take an idea and morph it into something totally different.