RB67 Multi angle grips

I was looking to pick up a multi angle grip for my RB. There are a few listings on KEH right now.

My question is - what is the spacer? There are 2 listings that are selling the grip, one with no adjustable shoe or spacer, the other just with no spacer. If I get one without a spacer, will that be something I'll still need to purchase?

Thanks

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