The Webcor looks like an early 50's model. I did a web search and came up with a website implying the Model 510 was manufactured by the John Meck Co. (
http://www.radioera.com/classic-literature.asp)
Looks like it would be a nice unit once restored. Don't know how much use you'd have for a mono turntable - you could replace the cartridge with one that complies with stereo discs but the trick would be finding one that would work with the heavy tonearm.