If it were me, I'd go New Cat Yellow, but that's me. I belong to an Board that is mostly Australians & New Zelanders, and I posted some questions about the Revell of Germany T900 kit; and the list on innacuarcies was huge. Here's what the Evan, owner of Melbourne Model Truck Accessories, had to say about it:
"The Revell T-900 "Australia" truck sure is one inaccurate model overall! You're right in that it is an early to late 70's W-900 extended hood. Over here in Oz we only had a handfull of extended hoods and the bulk of those had V12 Detroits.
The right hand dash is correct, and a welcome feature.
The 60" flat roof sleeper of that era is one that we never really saw a lot of here, as back then we had much more stringent wheelbase regulations, which is how the Australian SAR came about.
The engine range for the W-model from the 70's and 80's was the Cummins NTC and KT, Detroit 6V and 8V, and the Cat 3406 A and B.
The Cat 3408 was introduced in the early 80's I think, and from memory was only available in the cabovers.
The spider rims in the Revell kit are not the kind that Kenworth used either as most used the 6 spoke Malco hubs, and the closest spiders i've seen in a kit were in the ERTL Volvo N-10.
The bullbar isn't exactly what we would use here either. Most aussie bullbars are a lot flatter in the front.
Honestly, at the end of the day, if you really want to build a highly accurate Australian 80's W-model, I'd keep the chassis and cab and piff the rest!
All the parts you'd need are available, and I personally do the Aussie length W-925 bonnet to suit this kit as well as the Detroits, the rest you can get through Auslowe I think."