Yeah I thought about cutting out some plastic and somehow gluing it into place more flush with the carbody. My fear would be excess glue ruining it.
And someone also suggested the glass slide covers method. A local modeller has done it, said it was a bitch to do but the end result was pretty good and it has elicited positive comments. I will have to ask him how he did it as trimming slide covers has to be tricky I suspect. Once upon a time as a budding geologist I had a microscope kit and recall how fragile those covers were (good thing I had a um *cough!* cheap supply at school).
I don't know what brand this model is but the previous owner decorated the interior, changed out the railing on the observation platform with one of those thin etched brass kits, and the marker lamps actually light up.
The 'Fort' class cars was primarily used on the run from Vancouver to Penticton. An individual (he's sent me a handful of CPR CLC pics) gave me a list of some he's seen on that run during that era. This observation car was listed and it turns out that a model of it was for sale from a local collection that was being liquidated. It was the last car I needed to complete the train.
Not sure if you are aware but check this site: http://passcarphotos.info/Indices/CP1.htm