Michael, thank you for all this information!
The KB EXTRA's appear to have other stamps: http://straightrazorpalace.com/razor...xtra-67-a.html
I'm thinking that Kruse & Bahlmann is a more likely origin. K&B Hardware Co. sounds like they could have made a deal with Heljestrand for branded razors. But still, it has jimps(signifying a No. 23) but the tail looks like the MK23.
She is ready and I'll use her tomorrow for her first shave!