A little confused with your subject title and body of the message talking about two different things. But, the Tamiya Fletcher kit already has the fantail twin 40-mm tub. Yes an elevated centerline platform is needed in front of the bridge if using the Tamiya. But, that is easier to scratch make compared to other issues.

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Rick detailed most of the changes, but you also need the 20mm gun tub on the bridge face for the Tamiya kit
All in all, the ILK Stevens is better detailed (IMO). I am not a fan of the decal walkways in the Stevens kit