Generally Rosman is a "legitimate" company, but beware before putting an order through for anything you need in a timely manner (in stock or not).
If ordering online, for any item (whether it shows as being "in stock", "pre-order", "call-us" etc) on their website, they may or may not actually have stock.
There are many buyers who have ordered an item (including myself), and then had their order set to "pre-order". Rosman takes the entire value of the order, and is extremely poor with communication. My particular item it seems, has been ordered by many people weeks before me, who are also still waiting for an exact date on order availability.
I've also seen lots of people complain about a "fee" when trying to cancel/refund the order in these situations too; and the general suggestion has been to contact the ACCC and/or do a charge-back or PayPal dispute.
Had I known any of this beforehand, I wouldn't have ordered.
Rosman really has to improve its website stock visibility/communication.