No, with AppleShare 4.2.1 the AppleShare File Server application that you see in the Apple menu is really a facade application, and it does not really do the work of file sharing. The suggested memory allocation of 200K is all that is needed. There is no practical benefit from expanding the amount of memory for the application partition.
The file server program (strictly speaking, the File Server Extension) is an extension, and giving it more memory is not a finder operation. For more information on AppleShare File Server memory and cache, search for Technical Information Library article, "AppleShare 4.2.x: File Server Memory & Cache Usage."