Uh.... No. The Constitution model was clearly in Picard's Ready Room unless Riker's "office" also led directly from the door on the bridge and an inter-dimensional portal in the doorway somehow knew which room people wanted to enter.
The story I had always heard was that the model went missing from the Ready Room so that the filming model designers had a point-of reference for building the filming model. Maybe the Constitution-Class was place there as a way to make people think the Stargazer was a Constitution-Class (as that was obviously the idea at one point given the line-dubbing) but at some point the model was used as reference work for making the filming model (IIRC the Constitution model is still there in "The Battle" episode itself where the mis-direction was obviously not needed) bu, whatever the case for the model going missing, the Constitution model was always in Picard's Ready Room and never in "Riker's Office", if we even ever saw such a thing. (Which we didn't.)