There will be no second shipment from Japan. I don't expect Canadian prices go down.
Not all of them were surplussed by Japan. Many other nations had hundreds of thousands of them, in some cases millions of them left behind when the Japanese were thrown out or retreated leaving stores and in some cases factories producing them behind. China, Korea, Viet Nam, Thailand, Malaysia and many others adopted the captures for their own use. Some, like Korea opened the chambers/mag wells up to accept the 30-06 cartridge. The Chinese adapted the factory to produce them in 8x57. They issued the Japanese rifles, often without defacing the crests in its original cartridge until supplies of ammo and barrels ran out.
Thailand and many other East Asian nations have been selling off their warehouses full of arms surplus to their needs for years. The US pays them to destroy them through the UN. Likely other nations do as well.
I would like to be able to trek through some of the old reserve warehouses in Russia and some of the ex Soviet satellite nations. You can bet they still have some as well. No telling what condition they are in though.
When it comes to surplus, never say never. I have heard it over and over again that they aren't making anymore only to find out that they are or did until recently.
Let me give you some examples. Mauser 98 rifles. They are still being imported from all over Europe and South American countries. Mosin Nagants, Lee Enfields. Sadly South Africa recently destroyed thousands of Lee Enfield rifles dating back to the 1890s. This is a desperately poor nation and they destroyed these rifles and other equipment rather than releasing it onto the world market. A few years ago the folks from IMA in the US went through a facility that was destroying thousands of Long Lees that had been FTRed and put in storage in warehouses around Pretoria. The Greeks were destroying thousands of pristine Mannlichers according to John at Marstar around the same time. It was just cheaper to destroy them than what they could possibly get for them on the surplus market.
A few years back, Italy released several thousand Long Branch No4 MkI* rifles on the surplus market. We tried to get some brought into Canada but the people that owned them, even though many of them were North American companies felt there was a better market for them with higher prices in Europe.
Many nations still issue machine guns and sub machine guns from WWII. The most recent revelation came out of Syria, thousands of old new stock Stg44 assault rifles were released to the rebels. Who knows where they came from or how they got to Syria.
Never say never or there won't be any more coming when talking about milsurps becoming available again. It's all about money for the people that have to purchase them, proof them, mark them, market them, distribute them etc.