Kinross Junction

[grow45]

Since moving to Kinross I have taken an interest in the now long gone ex North British Railway station of Kinross Junction - which was about 500 metres from my new house.  I found this photo of the platform building which appears to have poster boards for the Glasgow and South Western Railway and the Great Central Railway on the end of it.  I had always assumed that these sorts of boards would only be used for the owning companies advertising but was that not the case?  Maybe they were rented out to other companies as a source of revenue or perhaps some sort of reciprocal advertising arrangement.  Any ideas?

Thanks