The two watches are radically different. The only similarity may be the colour of the numbers and dial.
I was struggling to decide between this and the 338. I picked the 338 because I think the lugs and crowns are more iconic of a radiomir.
The 512 just looks like a RAD-LUM offspring without much character tbh.
Having said that it is still a nice watch and if your only reservation is that it looks similar to your luminor than I'd say go for it as it is actually a very different style and will serve a very different purpose!
(Lol. Besides telling the time that is!!!
)