I'm trying to determine year of my frame.I think it might be 1931 because I read that was the year Indian started using 101 frame serial #'s[not sure if this info  is correct either].left side of frame at rear axle stay has 35-C-12-F & G4769. Right side by rear axle stay has 35-D-23 & maybe a faint 0. Neck has 1  35 D 5  & seat area has 1  35 D 9 &  right front frame downtube knuckle casting has 35 C 15. The DGP engine & trans fits in place with thru bolt frt mount. Not sure if rear brake frame bosses are the same for 1931 straight back and earlier cross over design. I see in pictures that rear wheel brake setup is different from 28-30 left outside band compared to 1931 right side drum. Any info is appreciated.  thanks again.

Your frame has a frame number, G 4769. Some few frames got a new axle plate with a boss for the number, but most didn't have that, the numbers are stamped on a plain axle plate. What you describe with the numbers starting with 35- is casting numbers that can be found on most all cast details.

You can't tell the year model by the frame numbers as they seems to be seqential and doesn't follow the engine numbers for what is known to the present, and the records are lost in history. The 31 frame is distinguished by the right side axle plate that has a very different shape than the earlier frames, but all the rest of the frame is exactly same from the first 101 to the last. 

The 31 axle plate in this picture is a bad example as it is repaired,but it shows the differences anyhow..