That's exactly what I did.
Top tree of the CB450 Project --->
And the one for the CB750 (still has to go on the bike) --->
I just ground the mounts down, had my chassis shop buddy fill in the holes with some alum. slag, then did some final grinding/sanding and I was done. The 450 tree I just painted, the cb750 tree I had powdercoated (after above pic was taken of course).
There is no need to spend the big cash on a aftermarket smooth tree when you can just take a stock piece, some time, and come
out with basically the same thing...