It comes after a supposedly late decision by Penrite to part company with Erebus Motorsport left the team little time to find new primary sponsors for its rookie pairing.
The oil company has since moved across to Kelly Grove Racing, backing David Reynolds and Andre Heimgartner.
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The championship freshmen recently tested at Winton Motor Raceway, sporting a temporary livery that will also be run at the official Supercars pre-season test.
Speaking on the Parked Up podcast, Ryan said a sponsor for Kostecki is all but locked in while the team could employ a Brad Jones Racing-style round-on-round revolving door of sponsorship deals for Brown.
“At the moment we will probably have two different cars,” said Ryan.
“With Penrite, how late they made their decision, it made it really difficult for us to try to get naming rights sponsors. But we've got Brodie's car definitely right to go, naming rights.
“We've got Will's pretty close. It could be two rounds here, one round here, bit of [what] Brad [Jones Racing] has been doing the last couple of years with Percat's car. But there's still a lot of shit going down which we're trying to sort.
“It's tough and big businesses that have the money to do it can't just make a decision overnight to spend what [they] need to spend and then you have got to manage merchandise and liveries and walling and uniforms and all that stuff.
“So we didn't want to rush out some livery that wasn't ready to go and a sponsor that wasn't ready to start activating so we did the test livery because we wanted to show this is the level we want to keep it at and be as professional and highly regarded with what we do with liveries as we can.
“We'll definitely bounce out something pretty special as soon as we can, probably in the lead-up to Bathurst. I think we'll still use that [black livery] for the test day and then we'll do something leading into the Bathurst week.”
Brown, 22, finished runner-up to Thomas Randle in last year's Super2 Series.
Kostecki, 23, was an early contender in the series title race, but missed the season-ending Bathurst 1000 after travel difficulties saw Eggleston Motorsport pull out.
The rookies will test at Winton Motor Raceway on February 16.