ok weird question

my gf bought an old m98 a while back. and wanted it to have a lil facelift lol. she said she wanted something girly, so i've milled the recievers slightly etc etc pretty basic stuff. and i was wondering. i have one of those little bouncy balls (its purple with a smiley face on it haha) that i was gunna make fit over the cocking knob as a lil over the top decoration lol. my question is, will that extra weight mess with the cycling of the gun? i know the rear bolt is already really heavy and i dont knwo if it's like weight balanced or something. i just dunno if adding a rubber ball to the mix would mess with it. any help??!!??

you do know if you ever use that gun in public your going to get made fun of, as for it making a difference, just try it and see if it works, if it dosent then take it off