MacBook MA 700 B/A Spacebar Key Cap

Apple MacBook MA 700 B/A [white] I need a spacebar key cap. Having looked at several websites there is apparently a choice of hinge mechanisms W1 and W2 this is a type W1 there are two hinge mechanisms for the space bar, one at each end. The only other bit of info I can find is Model ID 2,1. Is this sufficient information to identify the type of key cap needed, if so where can I get a replacement, any assistance information would be greatly appreciated. Thank you for reading this

i cant get mine back on

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