I have similar baseboard in my house, and recently replicated it. What I used is the molding bit set from Harbor Freight. One of the profiles is eerily close to the profile. I milled a rectangular piece in the correct dimensions, then milled the profile with my router table. I then cut a 9 degree angle on the bottom, and then squared the back to the angle cut. This thinned out the top edge, and kept the profile. I shellaced the molding with amber shellac, to more closely match the 1959 finish. You have to look really close to see the molding doesn't match exactly.
Tact is for people not witty enough to be sarcastic.