Conn 36K serial - oddity

[bstevens]

There's a Conn 36K for sale in decent condition but fairly pricey, but serial number is GE600157 - any ideas of the era or if that's even a CONN serial? All the charts I've seen have no mention of "GE", making me wonder if it's not an original valve-set or something? What's the sweet spot for these horns? I actually prefer a smaller bore as per the Kings, but everyone seems to suggest the pre-King 36K is better.

Thanks!