I have several. They are made in Canada Mossberg 500's. Made at the Lakefield factory. I love Made in Canada guns so....
They are IMHO the same as USA made ones of the same era. I would avoid any that have a single action bar(the bars connected to the pump and to the bolt. Early 12ga ones and some sub-guage models (20/410) have a single bar and it could bend under lots of force and cause some binding of the bolt during travel. I have 2 with singlebars and they work fine. Just be aware and keep them well lubed so there is less friction during recipricating the bolt.