Can I keep the Rueful Axe and get Clavicus Vile's Mask?

Is there a way to keep the Rueful axe and get Clavicus's Mask? I thought you could kill Barbas after receiving the mask, but he is a statue now. Did I miss my chance?

In this particular quest, you can not get both items as reward.

You either kill Barbas (poor mutt) and keep the Rueful Axe.

OR

Hand the axe to Clavicus Vile and receive his true daedric artifact, viz. the Masque of Clavicus Vile.

Important thing to note here is that only the Masque of Clavicus Vile counts towards the Oblivion Walker achievement.

I did try to be clever and decided not to kill Barbas before he turned to stone. This glitched my game worse than ever. Clavicus Vile's statue disappeared.

Please see this page on UESP for further information.

Easy, just press ` to open the console:

If you have taken the axe, type player.additem 000d2846 1
If you have taken the mask, type player.additem 0001c4e6 1