McGregor Golf Jacket Advertisement

This is an advertisement for McGregor golf jackets from Sports Illustrated (?) from the 50's...60's.....I'm not too sure. My interest in this item is due to the fact that the caddy in the background is my Grandfather. He was a Golf Course Superintendent and McGregor was shooting the ad one day and asked him to be in it. They did not pay him, my Grandfather asked for one of the jackets and they said no! This picture was not found until after he passed so my info on the ad is limited.

I need some help people....can anyone tell me: Year? Magazine? Anything!!??

Thanks in advance.