While it's a strong hint that Sea Fox may be selling to spheroids soon, I'm fairly certain promotional blurbs can't dictate canon availability on their own.
Availability also doesn't just mean "you can buy it", it means "you have bought it, and can call on a non-individual quantity for active use." At least, that's my one-sentence description, I'm sure Sartris and GreekFire could produce better summaries. While I'm sure that Sea Fox's opening of the flood gates to I.S. buyers would include an aggressive advertising campaign to every corner of the Sphere, it's not really I.S. General until every single active I.S. faction on the MUL buys or salvages a meaningful quantity.