Chrome Super Le Tour 12.2 Mysteries

 I've started to look the bike over a little more closely.  There are a few things that are mysterious.  Whoever owned it in the past added an odd mix of parts.

What's a Campagnolo headset doing on an old Schwinn?  But wait, the nut on the top is from Stronglight.

I suspect I cannot trust either to identify the actual maker of the headset.

The serial number on the headbadge is 1137.

This website on Schwinn serial numbers indicates that it was made on the 113th day of 1977.

That would be April 23rd.  But the serial number on the bottom bracket is -

It starts with "C7" which would seem to indicate March.

I haven't been able to look into it much further, but I'll continue working on it and polishing the chrome when I can.