Shaft mount roller rocker setup question

So I’m installing the valve train on my new 360 and my dart had came with 2 sets of rocker arms I could use. Trying to use the aluminum roller setup and the arms appear to be self aligning with the tabs on either side of the roller tip and spacers to keep the arms from contacting the shaft hold downs.

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So my only question is, does there need to be a spring/spacer in between the arms or do they not need one because they “should” align themselves on the valve stems?

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If there is something needed in between these arms I can’t use this setup because I don’t have it. These arms came in a coffee can in the back seat of my dart when I bought it. I do however have a set of new in box crane ductile iron arms with all the hardware.