You peeked my curiosity, so I went out to check all my machines. I would say that both the 400 series and 500 series and one of the 301s has a light brown lower area and a white (cream) in the upper area. So, I'm guessing it's one of those.
I would suggest that you can hardly go wrong with any old Singer machine. If it sews easily and sounds nice, it will work. The value is in whether the paint is in good condition, whether it comes with a case or cabinet, it's features (built in cams or not) and whether it has the accessories (extra cams, instruction book, extra feet and maybe a buttonholer). Those things, plus how badly the seller wants to sell and how badly you want the machine determines it's value.
You can get parts for Singer machines fairly easily and inexpensively, as the supply exceeds demand. There are exceptions, mostly those parts related to the Singer Featherweight. Those tend to be pricey.
Janey knows lots of stuff about all old sewing machines. I mostly know about the Singer slant shank machines. I have 9 of them. They are pretty much all the same on the inside and that's the machine I use.
Good luck with your purchase.
bkay