That's what it sounds like.
Mine only had one arm on it since I got it, and I didn't look too hard for another until this summer while in the woods a branch reached down and plucked the blade from the arm and flung it into oblivian. Then began the search for a blade that would mate to the original arm. No dice. So I began looking for an arm and blade combo. I found the Napa parts mentioned before to be close, but just close enough to build a false sense of trust, and then fail when you need them the most. Why are us guys so damn frugal that we can't just order the exact replacements from the surplus places?? For all the time I spent trying to make something work, I couldda just ordered the right part and been done.
Last week I was out exploring some new old mining trails, and I came upon an abandoned 5ton dumptruck, sunk in a swamp, trees groing up through the frame. I guess I'm an evil bastard 'cause I felt I needed the wipers more than it did.
But now I'm not quite a safety hazard on the road!!