Quick calculations:
2 oz is a sphere of about 2". Figure 1/8" thick glass and you have 2.25", the diameter of a cue ball.
The little grenade I have on my desk is 2.5" diameter (not the pineapple type), so it is close.
But, mine is not glass, it is OD green, and it has a pin and detonator plus a release lever. So, same size approximately but not at all similar.