That's definitely a 15 or a 115 with the gingerbread / Tiffany decals. My guess is a 115, but most of my clues are not in the photos. The easiest way to tell the difference is here, there are tons of photos to compare yours to:
http://www.quiltingboard.com/vintage...e-t216990.html
Lots of photos for you to compare with.
OK, The ISMACS list has been known to be wrong from time to time. It's mostly right though.
BUT -[TABLE]
[TR]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[/TABLE]
It's really easy to make mistakes with that list.
The G serial numbers for instance had up to 7 digits after the G.
If you look at the first "match" for your serial number:
[TABLE]
[TR]
[TD]G- [/TD]
[TD] 329001
[/TD]
[TD] 379000 [/TD]
[TD] 66
[/TD]
[TD] 50000 [/TD]
[TD] March 16
[/TD]
[TD] 1910
[/TD]
[/TR]
[/TABLE]
You get the 66 you thought it was. The problem with that is there are only 6 digits after the serial number. You need to go further down the list to the 7 digits. That tells us that it's a 115
Here's what I get when I look up your serial number:
[TABLE]
[TR]
[TD]G-
[/TD]
[TD] 3599476
[/TD]
[TD] 3604475
[/TD]
[TD] 115
[/TD]
[TD] 5000
[/TD]
[TD] April 28
[/TD]
[TD] 1914
[/TD]
[/TR]
[/TABLE]
This is a 115, and takes different bobbins than the 15 or the 66. The bobbin case is also different. The bobbins are easy to get though, they share with an industrial and some other domestic machines.