I just gave my White away on CL today. It was the 1755-plastic case, but metal innards, from the early 90's. That little machine chugged through a LOT of curtains, cushions, costumes, clothes, you name it.
I kept it as my backup when I got the Pfaff 130, but then I found the Nelco, and decided to keep that as my backup, and pass this one on to a new sewer in need of decent machine.
Also, you might consider putting a screwdriver and flashlight in your purse and going back to ask them if you can take the top off and check it out. If it's got the metal innards, I say go for it!