Some years of cavity-smoking as presented here. If a little is good, a lot more might be lots better......?
You know my views on Keith designs for revolvers......I have yet to find one I didn't like. The -423 wasn't made in huge numbers, and I just found mine (a recent-made Lyman 2-banger) in 2018. Given this is an Ideal tool, it was likely made during Mr. Keith's lifetime.
If there is a 'Flaw' in the Keith design, it is the over-generous lube groove in his oringinal design. That was OK if bear grease was your only option, but with even 50/50 lube you don't need that kind of capacity. Fill that space with drive band length--all 3 of them.