My father just turned 55 not too long ago. He was born in San Francisco, 1951.
On his 40th birthday, he receieved a 1951-S wheatback penny in his change at a store. Now, on his 55th Birthday, he receieved a 1951-S wheatback penny his his change at a store.
I want to buy him a 1951-S Penny, but they're so cheap and common I want to find one that's ultra-high grade. Make it more special since he does have two already

Is it hard to find a super high MS wheaty of that year/mint, and where would I look?