Welcome to the forum!
It seems you have at least the chassis of the 2355 WP F-3 locomotive. The 2355 WP F-3 has the horn in the 'A' non-powered unit as you describe.

You need to ascertain whether you have true 2345 shells. See the following descriptions for the differences in the 2345 and 2355 locomotive shells.

2345 http://www.postwarlionel.com/cgi-bin/postwar?ITEM=2345

2355 http://www.postwarlionel.com/cgi-bin/postwar?ITEM=2355

Look carefully at the nose handrails. This is the key to ascertaining what shells you have.

You may either have a 2345 shell on a 2355 chassis, or a 2355 locomotive with the wrong numberboards on the nose.

Larry