I would not say it is recommended but I think it is okay if the barrel is Cylinder Choke. If there is a choke to the barrel, I'd advise against it.
No published serial number data
Your westernfield model 550Al was made by mossberg for the montgomery wards co.(westernfield).These shotguns are still being made and are quite popular.I would check at mossberg,s site.The model designation for your wards shotgun made by mossberg is the mossberg model 500.