I think that the IPO is only on the Saudi exchange. So, unless your broker can trade on the Saudi exchange (and most can't), then you won't be able to participate.
I believe the Armco IPO is a sucker's bet. The company itself needed three years to get it's books in order for the IPO. Presumably, the look-back period is only three years. It wasn't (and IMO still isn't) run as a company, it's run as a department of the Saudi government. So, if the Saudi government needs more money, for say, a war in Yemen, or to fund ultra conservative Wahabbi madrases (schools) in Muslim countries, then who will be getting the bill? Aramco and Aramco only.
Another point is the valuation; MBS wanted $2 trillion for prestige reasons, not based on facts. He's getting somewhere between $1.5 and 1.75 trillion. Not much upside there and the resulting yield will be lower than comparable oil stocks in the West.
Bottom line: A sub-optimal investment that props up a dirty regime that is promoting values antithetical to those we in the West hold dear.