From Grand View Outdoors:

The new bill proposed by Baltimore delegate Jill Carter would bar the sale, possession or use of so-called “imitation firearms” and would impose a $1,000 fine and up to a year in prison for any violation. The bill defines imitation firearms as “a toy, a device or an object that substantially duplicates or can reasonably be perceived to be a firearm or a handgun.”

There is no so-called “grandfather clause,” so according to the legislation, anyone who owns a toy or an air gun that’s defined as an “imitation” would be violating the law.