Hi Jeff,
Sure. In SRT_UTIL you should see for one call 2 Requests and 2 Responses, if the call is successful. The reason for this, is that the first Request entry shows the content of the ABAP types, while the second shows the soap:Envelope generated from this data and transformed into XML.
Vica versa, the first response is the soap:Envelope, the second is the data converted to ABAP types.
So the answer to your question, is yes, SAP sends the logon data with the first request. As you already pointed out, the first request doesn't have any HTTP header data (button is missing), since it's not an HTTP request. It can be useful, when the transformation doesn't work properly, so you can compare the actual soap:Envelope with the ABAP data.
Cheers,
Attila