at this point i would definitely ask to see if it turns on. I bought a singer graduate sight unseen. When it arrived the entire machine was seized and wouldnt move. After copious amounts of oil and persistence i got it running. It now runs like a champ. But if you're unsure of your mechanical abilites then maybe you'd have to think about if your willing to spend time really learning your machine. Lol i love vintage machines because it does give ya satisfaction that you can fix up something that can make beautiful things. Vintage singers are awesome and if well taken cared of will last many years and may even outlast their owners.
So see if it turns on. If ya love it buy it. Learn from it, and it can change how you see modern machines differently.