The part numbers you quoted are late model wide body (ST & Ti) and narrow body (DX) steel bullbars, both of which are winch compatible. Not sure why you say they are stainless or why you think you need a "winch tray"...?
Can you post a pic of the bar?
There was only one stainless steel bullbar that was factory fitted (in Japan) but it was only available on very early GU's. This bar was compatible with a separate winch cradle.
All other "shiny" bars are locally developed Genuine Accessories manufactured for Nissan AUS by TJM from aluminium and are not winch compatible.
All black bullbars are also locally developed Genuine Accessories manufactured for Nissan AUS by ARB from powder coated mild steel and are all winch compatible. The winch bolts directly to the bar.