FWIW I would think that how a weapon _looks_ matters less than how it performs. If it shoots and injures/kills it doesn't matter to me if it's bright pink with rainbows and unicorns all over—it's still a perfectly valid weapon.

Looking like a toy could even serve as a useful form of camouflage.

Finally I would say that the fidelity of 3d printers is going up and the price is coming down. I would imagine that they won't look like they were sold at Toys-R-Us for much longer.