New to me Parker Grade V with questions...

[dan dwyer]

No, butt plate is not curved (from top to bottom). On the width, it tapers slightly on outer edges. Thanks for continued input.

[Bill Murphy]

The grip cap is a style that was available to American gunsmiths in the early 20th century. I have had older guns with this type of replacement grip caps.

[B. Dudley]

Then the buttplate is most likely not an actual Trojan plate if it is not curved. This type of buttplate was used on Many different guns. LC Smith, Ithaca, Savage/Stevens, Fox, etc... Not to mention several aftermarket plates too.