This could be a grey area. PC 12025 (f) states that firearms carried openly in a belt holster are not considered concealed.
The question is basically what does "carried openly" entail?
I know of no case law on this, and personally wouldn't want to be a test case.
An overzealous LEO might just take the partial concealment to mean that it is concealed. You might beat the rap, but you would still take the ride.
If you are going to Open Carry, then OPEN Carry, if you are going to Conceal Carry, then CONCEAL Carry.
Somewhere in the middle could slide either way in court.