Many of these top tier makers are just a couple steps bigger than boutique maker, shouldn't have inventory on the website as they are almost always out of everything, then make it. And they can (usually) make all with what's in stock; not like gun parts where they need a special part then it goes to the anodizer then... etc. If they want, they can usually turn around real fast.
If you need it now, call em up. They might very well make it and ship it on demand, or if you have a good excuse they will do it for you right away even if normally it would be a month.
Some won't. Busy, government contracts, plans, etc. But, worth an ask. Do not assume out of stock means 6 months.
Also: if in a hurry, sometimes the out of stock or delay is one color as they are out of fabric, hardware, etc in that color. Ask if you can get it faster in some other color.