I am not sure that I am the right person to answer your question. I work for the Department of Finance and tax collection, in 1992, was the responsibility of Revenue Canada. To my knowledge, the agreement with Quebec was an agreement between the Minister of Revenue Canada and the Minister of Revenue Quebec. It is therefore the responsibility of another department. My understanding is that the employees of Revenue Quebec are in a way proxies of the Minister of National Revenue as far as the administration of the GST is concerned.
So, questions relating to the administration of the tax and to verification should be put to representatives of CRA, the agency working with Revenue Quebec. They might be able to answer. Since the agreement is still valid, I suppose everything still works smoothly but I cannot give you any details.