Not a bad start, but probably way too late. Everyone uses the OSHWA logo regardless of whether their project is Open Source or not.
Unfortunately the concept of OSH has never really taken off, and most time products described as "Open Source Hardware" don't meet even the basic definition.
For example, Arduino do not publish design files for Arduino Zero. The first line of the OSHW definition says "1. Documentation
The hardware must be released with documentation including design files, and must allow modification and distribution of the design files". Yet Arduino claim the Zero is "fully Open Source". That claim is bullshit!
You can also look at the list of people who endorse OSHW and see how many don't follow the OSHW definition, while still claiming to be "Open Source." Names like Makerbot, OpenROV.
David Mellis who is involved with Arduino, is on the board of OSHWA. If even their own board members can't commit to their own OSH definition, what hope for anyone else?
I think the fact is that without a strong mover like Richard Stallman and FSF, the principles and practice get so diluted by commercial interest that the term Open Source Hardware becomes meaningless, and is just a marketing buzzphrase like "environmentally friendly".
Although Stallman didn't previously care about OSHW, he is now realising that to keep software open will require open hardware, as vendors lock in DRM into hardware, and breaking DRM is a criminal offence.