Thanks everyone!
You guys are fantastic.
I think that I phrased my strap question incorrectly. I meant to say that I wanted an "authentic" Bretling strap - it did not have to be original to this watch. In particular, I have seen alot of Cosmonaute's with bands leather bands with a deployment(?) clasp - those looked cool and I haven't ever seen them before. I have no idea who sells them
Also, I'm a bit hesitant to take this watch to my local watch repair guy to open it up. They seem to be a little rough sometimes and they don't cary many high-end type watches., but maybe I'm just being paranoid because I am still in the new-stage with this watch.
I have posted some pictures below to get some assessments. Damn - the watch looks kind of beat up in some of these photos. It never looked that bad in real life.

One of the things that concerned me was that the back was buffed smooth. Do people do that to hide serial numbers? I was trying to tilt it "just so" in the light to get a faint hint of the "Breitling" stamp.
Finally - and forgive me if this is a bad question - how much would be a "reasonable" price for this watch. I'm not sure if it is even possible to estimate from the photos that I posted. I paid about $3,200 US/2,200 Euros. Did I overpay for it?
Oh - One last thing.....
I saw a 125th anniversary Cosmonaute on the web, but there was no price listed and no way of finding out who sells them. Based on the mesurements it seems alot smaller than this one (41mm vs. 48mm).
Any opinions or thoughts on that one from anyone?
Thanks again for all of the great information!
I am learning alot from you all.