That's actually standard V cut checkering, just not cut too full depth. That leaves the tops of the diamonds flat.
It was very commonly done that way on late 1800 and early 1900 vintage shotguns.
They used very coarse checkering,,often 16LPI and coarser. 
14LPI is not uncommon. I had a Meriden SB shotgun that was checkered to 10LPI!

When you checker, the coarser the LPI (ess Lines per Inch), the deeper you have to cut the diamonds to create the sharp points/peaks.

Two things occur,,one is that it takes a lot more time to do that extra deep cutting
The other is that it really doesn't look all that good when the really coarse checkering is cut that deep enough get to diamond peaks.

So,,any LPI can be cut in that style inclu the very coarse LPI. Just don't cut the lines to full dpth to get the sharp peaks.

The lines still need to be cut to even depth. That will keep the flat tops an even size.

You don't need to go very deep to get this effect.
Cutting with a 75* checkering tool(s) looks better IMO than the usual 90*  tools. The lines will be narrower and have the appearance of greater depth.