If it were me, and I couldn't get my hands on a hydrometer, I'd go for it. My suspicion is that it's probably done. I've had fermentations stall, but I was using a rather obscure yeast, and my temps were a little low.
And next time you buy ingredients, add a couple hydrometers to the order. It's a good idea to have an extra sitting around. You never know when you'll need it.