The problem with welding thin items like this is that full penetration welds can easily become full-blow through holes. It does look like no weld-prep was done, but if you don't call for any you won't get any. The other factor is to look at the teensy weld section you'd end up with.

A better approach is to bevel, weld, grind flush, and then put a doubler plate over the joint and a fillet weld around the doubler, which will end up with about 10 times the shear area you have there.

It's hard to see how the inverted-V is to fit in, but it also has very little to work with.