Don,
Sorry to pile on buddy, but I, like others, have found a post where you looked up info on a Gravely G series for someone. I just picked up a 16G and a 20G and for a change they actually have the model and serial tags on them. So, if it's not too much trouble...
16G
Model 43780
Serial 0060306
20G
Model 41876
Serial 00586827
Any help is appreciated!
Larry