hidden tail gate hinge 57 ford

I was looking at the hidden tailgate hinge kits from Mar-k products. I want to use them on my 57 ford fleetside, the problem is they only make a kit for the stepside. I called and the tech person thought you could make it work on the fleetside, just wondering if anyone has done this. By looking at the instuction sheet I think it will work. Thanks for any info.