On 0307, I picked it up several years ago with 6750 miles on it. I ran it intermittently until 2017 when I rode it 7k miles to and from work, so I had a good feel for the stockers.
What I didn't know was the left main bearing had smoked before I got it but amazingly took that additional running time to really surface. I saved the cases by installing new leaded bronze bushings to eliminate the issue of differential expansion between the aluminum and old aluminum alloy lined steel shell bearing/bushing.
During the engine restoration I purchased the mounts you speak of from Atlantic. Only the fronts were replaced. I saw zero need to replace rear mounts. I noted the up/down movement was far less in magnitude, inferring that the new ones are stiffer. My old ones had settled some but I cannot say they were broken at all as they were fully intact when removed. So it actually does feel smoother at idle, but when riding I cant say as the weather this winter has had me mostly grounded. I felt the bike was relatively smooth before running down the highway. Since the new ones have been installed I put on a hundred fifty miles.
