Probably not now! What I suspect you had was a re-configured router - ie there was a config on ready for you. There is no archiving of configs within the router, you have the running config and the startup cnfig - most of the time those should be the same, and the factory defaults.

If you get a router that someone has part configured for you, and change the config, as long as you have not saved it, you can return to their config by simply reloading. |One you either erase the start or save your config, that has gone,