In fact you have few commands you can use to see how your model is rendered in game:
testmodel => insert a model in front of your current view, then you can turn around
testgun => insert a model as a gun model so it is attach to your current point of view
nextframe => by default, first frame is show, this command shows the next frame of the currently rendered model
prevframe => previous frame command
nextskin => when model uses skin, you can change the skin
prevskin => previous skin
For testmodel & testgun commands, first argument is the model path in your development PK3. You can set with a second argument the frame you want to render.
Be careful, testgun command will suppress your current selected weapon. The only way to get you weapon back is to use testmodel with a valid model. Then to clear the rendered model, just type "testmodel" with no model to render.
You should know you'll be the only one to see the model if you test it online
As example, try to use testmodel & testgun command with the current knife. Open your console and enter the following commands:
testgun models/weapons2/knife/v_knife 3
The model is expected as MD3 format, and yes, you need to create all the expected frames for each animation used in SG.
Here is the list of animations:
Weapon alternative fire
Weapon Special 2
Special animations can be avoided unless you have "special" animations, but then they must be handled by the code.
You should know current weapons have more then 100 frames each... but you may limit them if the result is fine