I imagine both are aftermarket keys. Your original probably had Briggs and Stratton on it but the one shown doesn't have enough wear for a 68 year old key. The GM marked on is currently available.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.