They're still making it, and it can be found in stock fairly easily. The hard thing is finding a Fluted Titanium Military. It's version that requires a lot of extra work and is a lot more difficult for them to produce, so they only make them in small batches. I think I read somewhere that they only make 25 of the Fluted Millie's a month. However, you pretty much never see them in stock. I think I also may have read somewhere that they had some issues and production halted for a while. I don't know if it has started again but I think they are supposed to become available soon and I don't think they're going to be discontinued or anything. They're just very low production and hard to get. They also cost at least $250 and even the dealers who get them new in stock often mark them up to $300 or $350 because they can only get their hands on a few and they know people will pay it. You can also get one new on eBay, but it will still cost you $350 to $400+.
The regular Ti Millie is easy to get and they all come with the steel lock bar insert now. I wish I knew somewhere where you could buy a replacement because I have a frankenstien Mille with the brown g10/CTS-XHP blade steel and a Titanium locking side (I will post pics below) and my steel bar has worn quite a bit. I don't know if it's just the CTS-XHP being very hard and maybe the S30V blade tang wouldn't be so hard on the steel insert, but the still insert WILL ware. I don't know how much mine was opened and closed before I bought it (the previous owner mated the Ti with the brown/CTS-XHP), but the sharp corner of the blade tang began to ware a little wedge into the lock bar insert. Aside from waring like a normal Ti lock bar face would and making the lockup gradually later, this wouldn't be a problem. However, since the lock bar insert extends a little past the bottom of the blade tang, a small portion of the insert didn't get worn since it was that slight bit that didn't make contact with the tang. This resulted in a little notch that when you would grip the handle of the knife, it would kind of click and make you feel like you were flexing the lock bar (which bugged the hell out of me because it made an otherwise perfect knife feel flawed/flimsy). I realize this is probably really hard to understand without seeing the knife and see what I mean, but basically, I had to take the steel insert out and grind that little notch of and grind the face of the insert smooth again so it would function smoothly. Again, not a problem, accept for the fact that now the lockup is at about 70 percent and it's normally at about 30 with these knives. That's not a big problem either, accept for the tang of a Millie is radiused quite a bit, like older Strider's, and this knife will probably develop lock rock eventually if it gets worn much closer to the extreme part of that radius.
So, I want to get a replacement insert (or two, because I intend to keep this knife forever as this combo makes for one of the coolest Millie's I've ever seen). The problem is since this knife is a frankenstien project, Spyderco will instantly know that the knife has been taken apart, which voids the warranty. I also can't put it back together with the original blade and Ti scale to make it looks stock because I didn't buy the two other halves of the knife. Furthermore, I'm not the original owner of either of these two knives anyway. So I'd be surprised if Spyderco did anything to help me with this issue. I could call them and ask for a replacement insert, but considering you void your warranty by taking the knife apart at all, I doubt they mail out parts like that, the way Kershaw does.
To answer the OP's question, I do think you'd be fine if you bought one because Spyderco will always replace that insert if it ever wears out (unless you're in a situation like mine). That's half the reason it's there - so the lock up will wear out much slower and so it can always be replaced. But I don't think you can just call them and order one and I don't think you can just buy one from a Spyderco dealer. Unless I get really lucky, I think my only option is going to be to carefully fabricate an identical new insert.
