That's not what I'm saying. Re-read my post.
I'm not saying that he had *both* of his guns during the arena battle, nor am I saying that he didn't lose one to Obi-Wan.
What I *am* saying, is that I doubt Jango, being the type of guy that he is, would only own *2* firearms. Sure, he has his gauntlets, his jet pack, and his knees, all of which offer him offensive capabilities, but they're just not the same as having "a trusty blaster at your side"...
You know that he had to have one or two (or maybe more) squirreled away someplace in case he needed a fallback, or for a "rainy day" situation. And yeah, he could have even stashed one on Slave I in case one (or both) were destroyed during an off-world adventure and he needed to re-arm himself. I guess I could say that Boba's sidearm is an "extra" Westar that he discovered onboard Slave I or something.
I just finished sewing up my holster, so it's too late to turn back now!
Thousands of possibilites exist, and I'm running with them!
And what IS it with all of these Jedi cutting off the barrels of Fett family guns?!? What's up with that?
Hindsight being 20/20, if Boba saw Mace cut Jango's Westar in half, he SHOULD have been expecting it when Luke chopped his own EE-3 in ROTJ... :rolleyes