I've seen that knob for sale before but it's a pretty poor copy to be bluntly honest. Thanks for posting it though!
The top of an original knob isn't flat and has facets that continue to the emblem. The base isn't shaped correctly and the emblem relief is too deep.
BTW, the replica emblems are perfect to original!
Here's a couple poor pics of my knobs that I had cast. This is a rough casting and unfinished but you get the idea. I have a machined aluminum master to cast more as needed.
Larry